ComboBox selection generating list for another comboBox question
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Almost there.....maybe. I'm having object type issues: I've cleaned things up and have the following:
private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, DataGridViewCellEventArgs e)
{string strPrimary = dataGridView1\[e.ColumnIndex, e.RowIndex\].Value.ToString(); Debug.WriteLine(strPrimary); if (strPrimary == "Test1") { //Build a list var dataSource = new List<Units>(); dataSource.Add(new Units() { Unit = "blah1" }); dataSource.Add(new Units() { Unit = "blah2" }); dataSource.Add(new Units() { Unit = "blah3" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; } } private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb = e.Control as ComboBox; if (cb != null) { // first remove event handler to keep from attaching multiple: cb.SelectedIndexChanged -= column1DataGridViewComboBox\_SelectedIndexChanged; // now attach the event handler cb.SelectedIndexChanged += column1DataGridViewComboBox\_SelectedIndexChanged; } }I get "No overload for 'column1DataGridViewComboBox_SelectedIndexChanged' matches delegate 'System.EventHandler'" However, as you probably know, I can change
private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, DataGridViewCellEventArgs e)
to
private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
which fixes that. But I need the DataGridViewCellEventArgs class to access the ColumnIndex and RowIndex properties. Thoughts?
For the
SelectedIndexChangedhandler, you don't need the Column and Row because each time the handler gets called it is called by the relevantComboBox. Therefore you can get at theComboBoxby Casting thesenderparameter. Here we go again. :-Dprivate void column1DataGridViewComboBox\_SelectedIndexChanged(object sender, EventArgs e) { ComboBox cb = sender as ComboBox; string someString = cb.SelectedItem; // OR int cbIndex = cb.SelectedIndex; // and so on }or, to do it the longer, more difficult to read way
private void column1DataGridViewComboBox\_SelectedIndexChanged(object sender, EventArgs e) { string someString = ((ComboBox)sender).SelectedItem; // OR int cbIndex = ((ComboBox)sender).SelectedIndex; // and so on }Good luck! :)
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Why do programmers often confuse Halloween and Christmas? Because 31 Oct = 25 Dec.
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For the
SelectedIndexChangedhandler, you don't need the Column and Row because each time the handler gets called it is called by the relevantComboBox. Therefore you can get at theComboBoxby Casting thesenderparameter. Here we go again. :-Dprivate void column1DataGridViewComboBox\_SelectedIndexChanged(object sender, EventArgs e) { ComboBox cb = sender as ComboBox; string someString = cb.SelectedItem; // OR int cbIndex = cb.SelectedIndex; // and so on }or, to do it the longer, more difficult to read way
private void column1DataGridViewComboBox\_SelectedIndexChanged(object sender, EventArgs e) { string someString = ((ComboBox)sender).SelectedItem; // OR int cbIndex = ((ComboBox)sender).SelectedIndex; // and so on }Good luck! :)
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Why do programmers often confuse Halloween and Christmas? Because 31 Oct = 25 Dec.
Wait, let me take my earplugs out....Oh yes, now I think I can see :-D
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
ComboBox cb = e.Control as ComboBox;
if (cb != null)
{
// first remove event handler to keep from attaching multiple:
cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged;
// now attach the event handler
cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
}Since DataGridViewEditingControlShowingEventArgs is handling the EditingControlShowing event and will be passing the arguments to the SelectedIndexChanged event handle, the SelectedIndexChanged event cannot have a handling class that is trying to control the same thing at the same time (in this case the ComboBox). Do you concur?
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Wait, let me take my earplugs out....Oh yes, now I think I can see :-D
private void dataGridView1_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e)
{
ComboBox cb = e.Control as ComboBox;
if (cb != null)
{
// first remove event handler to keep from attaching multiple:
cb.SelectedIndexChanged -= column1DataGridViewComboBox_SelectedIndexChanged;
// now attach the event handler
cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
}Since DataGridViewEditingControlShowingEventArgs is handling the EditingControlShowing event and will be passing the arguments to the SelectedIndexChanged event handle, the SelectedIndexChanged event cannot have a handling class that is trying to control the same thing at the same time (in this case the ComboBox). Do you concur?
mprice214 wrote:
Since DataGridViewEditingControlShowingEventArgs is handling the EditingControlShowing event and will be passing the arguments to the SelectedIndexChanged event handle
I think that you have slightly misunderstood what is happening here. The
EditingControlShowinghandler does not pass any arguments, it simply tells theComboBoxwhere to find the code to execute when itsSelectedIndexchanges and regardless of whatever else is going on it will fire off that code when the index does change. Of course it may not execute it instantly, not even modern computers can really do more than one thing at a time. It has just occurred to me that you are actually asking about the '-=' and '+=' bits. They are like that because theSelectedIndexChangedcontains a list of methods that it should execute. If we used the '+=' line only, then each time we did so another instance of thecolumn1DataGridViewComboBox_SelectedIndexChangedwould be added to the list meaning that it would execute once after the first time, twice after the second, three times...... You get the idea. So we first '-=' it to remove the handler from the list, before adding it again. Of course we could test to see if it was there already NOTE** this is not real codeif (!cb.SelectedIndexChanged.List.Contains(column1DataGridViewComboBox_SelectedIndexChanged))
{
cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
}oops forgot to close the tag. but the '-=' then '+=' method is quicker. Hope that this helps. :)
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Why do programmers often confuse Halloween and Christmas? Because 31 Oct = 25 Dec.
modified on Wednesday, May 19, 2010 10:31 AM
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mprice214 wrote:
Since DataGridViewEditingControlShowingEventArgs is handling the EditingControlShowing event and will be passing the arguments to the SelectedIndexChanged event handle
I think that you have slightly misunderstood what is happening here. The
EditingControlShowinghandler does not pass any arguments, it simply tells theComboBoxwhere to find the code to execute when itsSelectedIndexchanges and regardless of whatever else is going on it will fire off that code when the index does change. Of course it may not execute it instantly, not even modern computers can really do more than one thing at a time. It has just occurred to me that you are actually asking about the '-=' and '+=' bits. They are like that because theSelectedIndexChangedcontains a list of methods that it should execute. If we used the '+=' line only, then each time we did so another instance of thecolumn1DataGridViewComboBox_SelectedIndexChangedwould be added to the list meaning that it would execute once after the first time, twice after the second, three times...... You get the idea. So we first '-=' it to remove the handler from the list, before adding it again. Of course we could test to see if it was there already NOTE** this is not real codeif (!cb.SelectedIndexChanged.List.Contains(column1DataGridViewComboBox_SelectedIndexChanged))
{
cb.SelectedIndexChanged += column1DataGridViewComboBox_SelectedIndexChanged;
}oops forgot to close the tag. but the '-=' then '+=' method is quicker. Hope that this helps. :)
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Why do programmers often confuse Halloween and Christmas? Because 31 Oct = 25 Dec.
modified on Wednesday, May 19, 2010 10:31 AM
Henry Minute wrote:
I think that you have slightly misunderstood what is happening here.
That's a surprise. :^) Got it, but also SelectedIndexChanged cannot access the control via DataGridViewCellEventArgs because the control is accessed via EditingControlShowing with the DataGridViewEditingControlShowingEventArgs class, correct?
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Henry Minute wrote:
I think that you have slightly misunderstood what is happening here.
That's a surprise. :^) Got it, but also SelectedIndexChanged cannot access the control via DataGridViewCellEventArgs because the control is accessed via EditingControlShowing with the DataGridViewEditingControlShowingEventArgs class, correct?
Ah now I understand.
mprice214 wrote:
also SelectedIndexChanged cannot access the control via DataGridViewCellEventArgs because the control is accessed via EditingControlShowing with the DataGridViewEditingControlShowingEventArgs class, correct?
No, that is not quite right. The reason is that each event handler has its own, internally defined, set of parameters, that you have to adhere to. Most event handlers have the
object sender(in fact I can't think of one off the top of my head that doesn't) after that most also have some form ofEventArgsand if the internal definition says it has to have a plain old EventArgs, then it will only work with EventArgs. If the definition says it should have anDataGridViewCellEventArgsthen it will only work if you declare it with one of those. SelectedIndexChanged has an EventArgs because it doesn't need to pass any additional information. You know who sent it from thesenderparameter. The fact that the event has fired means that the SelectedIndex of the sender has changed and that is all the information you need to make use of it DataGridViewEditingControlShowingEventArgs holds additional information about where in the DataGridView (Column, Row) the event was fired from.Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Why do programmers often confuse Halloween and Christmas? Because 31 Oct = 25 Dec.
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Ah now I understand.
mprice214 wrote:
also SelectedIndexChanged cannot access the control via DataGridViewCellEventArgs because the control is accessed via EditingControlShowing with the DataGridViewEditingControlShowingEventArgs class, correct?
No, that is not quite right. The reason is that each event handler has its own, internally defined, set of parameters, that you have to adhere to. Most event handlers have the
object sender(in fact I can't think of one off the top of my head that doesn't) after that most also have some form ofEventArgsand if the internal definition says it has to have a plain old EventArgs, then it will only work with EventArgs. If the definition says it should have anDataGridViewCellEventArgsthen it will only work if you declare it with one of those. SelectedIndexChanged has an EventArgs because it doesn't need to pass any additional information. You know who sent it from thesenderparameter. The fact that the event has fired means that the SelectedIndex of the sender has changed and that is all the information you need to make use of it DataGridViewEditingControlShowingEventArgs holds additional information about where in the DataGridView (Column, Row) the event was fired from.Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Why do programmers often confuse Halloween and Christmas? Because 31 Oct = 25 Dec.
-
Ah now I understand.
mprice214 wrote:
also SelectedIndexChanged cannot access the control via DataGridViewCellEventArgs because the control is accessed via EditingControlShowing with the DataGridViewEditingControlShowingEventArgs class, correct?
No, that is not quite right. The reason is that each event handler has its own, internally defined, set of parameters, that you have to adhere to. Most event handlers have the
object sender(in fact I can't think of one off the top of my head that doesn't) after that most also have some form ofEventArgsand if the internal definition says it has to have a plain old EventArgs, then it will only work with EventArgs. If the definition says it should have anDataGridViewCellEventArgsthen it will only work if you declare it with one of those. SelectedIndexChanged has an EventArgs because it doesn't need to pass any additional information. You know who sent it from thesenderparameter. The fact that the event has fired means that the SelectedIndex of the sender has changed and that is all the information you need to make use of it DataGridViewEditingControlShowingEventArgs holds additional information about where in the DataGridView (Column, Row) the event was fired from.Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” Why do programmers often confuse Halloween and Christmas? Because 31 Oct = 25 Dec.
Guess who. I have the following:
private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
{ComboBox cb = sender as ComboBox; string strPrimary = cb.SelectedItem.ToString(); Debug.WriteLine(strPrimary); var dataSource = new List<Units>(); switch (strPrimary) { case "1": //Build a list dataSource.Add(new Units() { Unit = "blah1" }); dataSource.Add(new Units() { Unit = "blah2" }); dataSource.Add(new Units() { Unit = "blah3" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case "2": //Build a list dataSource.Add(new Units() { Unit = "blah4" }); dataSource.Add(new Units() { Unit = "blah5" }); dataSource.Add(new Units() { Unit = "blah6" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case "3": //Build a list dataSource.Add(new Units() { Unit = "blah7" }); dataSource.Add(new Units() { Unit = "blah8" }); dataSource.Add(new Units() { Unit = "blah9" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; } }Well, the problem of course as you know is that ComboBox cb points to the second comboBox once I select it. In fact, once I select a value on the first comboBox and then select the second comboBox to select a value, debug.writeline gives me "WindowsFormsApplication1.Form1+Units" (although the 2nd comboBox does get populated with the appropriate list based upon the selection of the first comboBox). If I use an integer instead of strPrimary and set it as cb.SelectedIndex, what I actually get from debug is the index of the selection of the list of the second comboBox (eg if blah5 is selected, I get an integer = 1) followed by an integer
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Guess who. I have the following:
private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
{ComboBox cb = sender as ComboBox; string strPrimary = cb.SelectedItem.ToString(); Debug.WriteLine(strPrimary); var dataSource = new List<Units>(); switch (strPrimary) { case "1": //Build a list dataSource.Add(new Units() { Unit = "blah1" }); dataSource.Add(new Units() { Unit = "blah2" }); dataSource.Add(new Units() { Unit = "blah3" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case "2": //Build a list dataSource.Add(new Units() { Unit = "blah4" }); dataSource.Add(new Units() { Unit = "blah5" }); dataSource.Add(new Units() { Unit = "blah6" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case "3": //Build a list dataSource.Add(new Units() { Unit = "blah7" }); dataSource.Add(new Units() { Unit = "blah8" }); dataSource.Add(new Units() { Unit = "blah9" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; } }Well, the problem of course as you know is that ComboBox cb points to the second comboBox once I select it. In fact, once I select a value on the first comboBox and then select the second comboBox to select a value, debug.writeline gives me "WindowsFormsApplication1.Form1+Units" (although the 2nd comboBox does get populated with the appropriate list based upon the selection of the first comboBox). If I use an integer instead of strPrimary and set it as cb.SelectedIndex, what I actually get from debug is the index of the selection of the list of the second comboBox (eg if blah5 is selected, I get an integer = 1) followed by an integer
Aaaaand relax! I think I know what is going on here. If you recall, well even if you don't recall actually :) , in my second message to you I had this bit of code: (I've annotated it a bit and modified it v,v slightly)
private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; // switch (dataGrid.CurrentCell.ColumnIndex) <===================================== silly! already have column in eventargs switch (e.Column) //<==============================Use this instead { case 0: // use the index for your comboboxcolumn <============ **V IMPORTANT** make sure that the 0: matches the index for your column cb = e.Control as ComboBox; if (cb != null) { // first remove event handler to keep from attaching multiple: cb.SelectedIndexChanged -= column1DataGridViewComboBox\_SelectedIndexChanged; // now attach the event handler cb.SelectedIndexChanged += column1DataGridViewComboBox\_SelectedIndexChanged; } break; // <================================== You do not need the part below since you only need it to apply to the first cbcolumn //case 3: // use the index for your second combo // cb = e.Control as ComboBox; // if (cb != null) //{ // first remove event handler to keep from attaching multiple: // cb.SelectedIndexChanged -= cb\_SecondSelectedIndexChanged; // now attach the event handler // cb.SelectedIndexChanged += cb\_SecondSelectedIndexChanged; //} //break; } }If you can absolutely guarantee that you will only want to do this for one
ComboBoxColumnyou can simplify the code slightly.private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; // replace the switch statement by an if statement if (e.Column == 0) //<============ **V IMPORTANT** change the 0 (if necessary) to match the index for your column { cb = e.Control as ComboBox; if (cb != null) { // first remove event handler to keep from attaching multiple: cb.Selec -
Aaaaand relax! I think I know what is going on here. If you recall, well even if you don't recall actually :) , in my second message to you I had this bit of code: (I've annotated it a bit and modified it v,v slightly)
private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; // switch (dataGrid.CurrentCell.ColumnIndex) <===================================== silly! already have column in eventargs switch (e.Column) //<==============================Use this instead { case 0: // use the index for your comboboxcolumn <============ **V IMPORTANT** make sure that the 0: matches the index for your column cb = e.Control as ComboBox; if (cb != null) { // first remove event handler to keep from attaching multiple: cb.SelectedIndexChanged -= column1DataGridViewComboBox\_SelectedIndexChanged; // now attach the event handler cb.SelectedIndexChanged += column1DataGridViewComboBox\_SelectedIndexChanged; } break; // <================================== You do not need the part below since you only need it to apply to the first cbcolumn //case 3: // use the index for your second combo // cb = e.Control as ComboBox; // if (cb != null) //{ // first remove event handler to keep from attaching multiple: // cb.SelectedIndexChanged -= cb\_SecondSelectedIndexChanged; // now attach the event handler // cb.SelectedIndexChanged += cb\_SecondSelectedIndexChanged; //} //break; } }If you can absolutely guarantee that you will only want to do this for one
ComboBoxColumnyou can simplify the code slightly.private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; // replace the switch statement by an if statement if (e.Column == 0) //<============ **V IMPORTANT** change the 0 (if necessary) to match the index for your column { cb = e.Control as ComboBox; if (cb != null) { // first remove event handler to keep from attaching multiple: cb.SelecGood morning (or whatever time of day it is to you). DataGridViewEditingControlShowingEventArgs does not contain the "column" method. I do remember your second message and did try to do that yesterday without success. Let me give you both methods together:
private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
{ComboBox cb = sender as ComboBox; int intPrimary = cb.SelectedIndex; Debug.WriteLine(intPrimary + "SelectedIndexChanged"); var dataSource = new List<Units>(); switch (intPrimary) { case 0: //Build a list dataSource.Add(new Units() { Unit = "blah1" }); dataSource.Add(new Units() { Unit = "blah2" }); dataSource.Add(new Units() { Unit = "blah3" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case 1: //Build a list dataSource.Add(new Units() { Unit = "blah4" }); dataSource.Add(new Units() { Unit = "blah5" }); dataSource.Add(new Units() { Unit = "blah6" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case 2: //Build a list dataSource.Add(new Units() { Unit = "blah7" }); dataSource.Add(new Units() { Unit = "blah8" }); dataSource.Add(new Units() { Unit = "blah9" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; } } private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing"); switch (dataGridView1.CurrentCell.ColumnIndex) { case 0: cb = e.Contr -
Good morning (or whatever time of day it is to you). DataGridViewEditingControlShowingEventArgs does not contain the "column" method. I do remember your second message and did try to do that yesterday without success. Let me give you both methods together:
private void column1DataGridViewComboBox_SelectedIndexChanged(object sender, EventArgs e)
{ComboBox cb = sender as ComboBox; int intPrimary = cb.SelectedIndex; Debug.WriteLine(intPrimary + "SelectedIndexChanged"); var dataSource = new List<Units>(); switch (intPrimary) { case 0: //Build a list dataSource.Add(new Units() { Unit = "blah1" }); dataSource.Add(new Units() { Unit = "blah2" }); dataSource.Add(new Units() { Unit = "blah3" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case 1: //Build a list dataSource.Add(new Units() { Unit = "blah4" }); dataSource.Add(new Units() { Unit = "blah5" }); dataSource.Add(new Units() { Unit = "blah6" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; case 2: //Build a list dataSource.Add(new Units() { Unit = "blah7" }); dataSource.Add(new Units() { Unit = "blah8" }); dataSource.Add(new Units() { Unit = "blah9" }); //Setup data binding this.column2DataGridViewComboBox.DataSource = dataSource; this.column2DataGridViewComboBox.DisplayMember = "Unit"; break; } } private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing"); switch (dataGridView1.CurrentCell.ColumnIndex) { case 0: cb = e.Contrmprice214 wrote:
DataGridViewEditingControlShowingEventArgs does not contain the "column" method.
:-D That's what you get for trying to code off the top of your head. Good to see that you were smart enough to use the correct form.:thumbsup: Once again I think I have worked out what is happening. In order to save on system resources, dear old M$ are using the same
ComboBoxfor allComboBoxCells and just hiding it, rather than destroying it, when not needed. Because it is just hidden, the link to theSelectedIndexChangednever gets deleted, which is why it occurs for column2 as well. After very little thought I see three ways to handle the problem: 1. in theSelectedIndexChangedhandler test for the column index before anything else and bomb out (a technical term :) ) if not the one we want.private void column1DataGridViewComboBox\_SelectedIndexChanged(object sender, EventArgs e) { if (dataGridView1.CurrentCell.ColumnIndex != 0) // <=========== Bombing out construct { return; } ComboBox cb = sender as ComboBox; int intPrimary = cb.SelectedIndex; Debug.WriteLine(intPrimary + "SelectedIndexChanged"); ................................ ................................ ................................ ................................ }2. in the
EditingControlShowinghandler remove the link when we don't find the column we want.private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing"); switch (dataGridView1.CurrentCell.ColumnIndex) { case 0: cb = e.Control as ComboBox; if (cb != null) { // first remove event handler to keep from attaching multiple: cb.SelectedIndexChanged -= column1DataGridViewComboBox\_SelectedIndexChanged; // now attach the event handler cb.SelectedIndexChanged += column1DataGridViewComboBox\_SelectedIndexChanged; } break; default: -
mprice214 wrote:
DataGridViewEditingControlShowingEventArgs does not contain the "column" method.
:-D That's what you get for trying to code off the top of your head. Good to see that you were smart enough to use the correct form.:thumbsup: Once again I think I have worked out what is happening. In order to save on system resources, dear old M$ are using the same
ComboBoxfor allComboBoxCells and just hiding it, rather than destroying it, when not needed. Because it is just hidden, the link to theSelectedIndexChangednever gets deleted, which is why it occurs for column2 as well. After very little thought I see three ways to handle the problem: 1. in theSelectedIndexChangedhandler test for the column index before anything else and bomb out (a technical term :) ) if not the one we want.private void column1DataGridViewComboBox\_SelectedIndexChanged(object sender, EventArgs e) { if (dataGridView1.CurrentCell.ColumnIndex != 0) // <=========== Bombing out construct { return; } ComboBox cb = sender as ComboBox; int intPrimary = cb.SelectedIndex; Debug.WriteLine(intPrimary + "SelectedIndexChanged"); ................................ ................................ ................................ ................................ }2. in the
EditingControlShowinghandler remove the link when we don't find the column we want.private void dataGridView1\_EditingControlShowing(object sender, DataGridViewEditingControlShowingEventArgs e) { ComboBox cb; Debug.WriteLine(dataGridView1.CurrentCell.ColumnIndex + "EditControlShowing"); switch (dataGridView1.CurrentCell.ColumnIndex) { case 0: cb = e.Control as ComboBox; if (cb != null) { // first remove event handler to keep from attaching multiple: cb.SelectedIndexChanged -= column1DataGridViewComboBox\_SelectedIndexChanged; // now attach the event handler cb.SelectedIndexChanged += column1DataGridViewComboBox\_SelectedIndexChanged; } break; default:Thanks for your help on this. I was able to become much more familiar with the event handlers. I began focusing on DataGridView FAQ Appendix A, 18 that you mentioned a bit ago. I was trying to get that going and was still having some issues and then came across http://social.msdn.microsoft.com/forums/en-US/winformsdatacontrols/thread/6f6c2632-afd7-4fe9-8bf3-c2c8c08d1a31/[^] Anyway, I'll have to tweak it a bit to keep users from pulling down the second comboBox first (which will throw and exception), but it's exactly what I need. Anyway, you taking the time really helped me out to understand some "basic" things that will help me get through the rest of this project. Thanks again.
public partial class Form1 : Form
{
DataTable tblPrimary, tblSecondary;
BindingSource primaryBS, filteredSecondaryBS, unfilteredSecondaryBS;public Form1() { tblPrimary = new DataTable("Primary"); tblPrimary.Columns.Add("ID", typeof(int)); tblPrimary.Columns.Add("Name", typeof(string)); tblSecondary = new DataTable("Secondary"); tblSecondary.Columns.Add("ID", typeof(int)); tblSecondary.Columns.Add("subID", typeof(int)); tblSecondary.Columns.Add("Name", typeof(string)); tblPrimary.Rows.Add(new object\[\] { 0, "Force" }); tblPrimary.Rows.Add(new object\[\] { 1, "Torque" }); tblPrimary.Rows.Add(new object\[\] { 2, "Pressure" }); tblSecondary.Rows.Add(new object\[\] { 0, 0, "lb" }); tblSecondary.Rows.Add(new object\[\] { 1, 0, "N" }); tblSecondary.Rows.Add(new object\[\] { 2, 0, "oz" }); tblSecondary.Rows.Add(new object\[\] { 3, 1, "in-lb" }); tblSecondary.Rows.Add(new object\[\] { 4, 1, "ft-lb" }); tblSecondary.Rows.Add(new object\[\] { 5, 1, "N-m" }); tblSecondary.Rows.Add(new object\[\] { 6, 2, "PSI" }); tblSecondary.Rows.Add(new object\[\] { 7, 2, "Pa" }); tblSecondary.Rows.Add(new object\[\] { 8, 2, "bar" }); InitializeComponent(); primaryBS = new BindingSource(); primaryBS.DataSource = tblPrimary;