How set the background of an MDI container window?
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Not to mention using a try/catch to find the correct control is slow as exceptions are expensive objects to create. Exceptions should be used to handle exceptional cases, not used in main logic. A much better and faster implementation would have been to check the type of the control first, then cast it to an MdiClient if appropriate.
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Dave KreskowiakThat's funny considering this comes from Microsoft's own help and support on the subject. http://support.microsoft.com/kb/319417[^]
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That's funny considering this comes from Microsoft's own help and support on the subject. http://support.microsoft.com/kb/319417[^]
I don't care. Those examples are not there to demo best practices. Those examples are not considered "production-level" code.
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Dave Kreskowiak -
I don't care. Those examples are not there to demo best practices. Those examples are not considered "production-level" code.
A guide to posting questions on CodeProject[^]
Dave KreskowiakI'm so glad your opinion isn't all that matters then.
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I'm so glad your opinion isn't all that matters then.
I'm not the only one telling you the practice sucks...
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Dave Kreskowiak -
I'm not the only one telling you the practice sucks...
A guide to posting questions on CodeProject[^]
Dave KreskowiakAnd yet neither of you are displaying an alternative that is better?
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You can set the background by casting the type to MDIClient and setting the MDIClient background. EXAMPLE:
private void Form1\_Load(object sender, EventArgs e) { MdiClient ctlMDI; //' Loop through all of the form's controls looking //' for the control of type MdiClient. foreach (Control ctl in this.Controls) { try { // Attempt to cast the control to type MdiClient. ctlMDI = (MdiClient)ctl; // Set the BackColor of the MdiClient control. ctlMDI.BackColor = Color.White; } catch (InvalidCastException exc) { // Catch and ignore the error if casting failed. } } }Hi, I don't think you deserve to be cast into the outer darkness of the dreaded one-vote here, because you were, I think, sincerely trying to respond to the OP's question. And, whether the code you provided leads to gnashing of teeth, or not, it does work. But, may I suggest, in the future, you provide a link to the MS docs, or other sources, code examples are taken from. best, Bill
"Last year I went fishing with Salvador Dali. He was using a dotted line. He caught every other fish." Steven Wright
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You could, but it's worthess and will slow down your applications rendering speed. Again, you can't do it as design time. You have to do it at runtime. Again, you have to enumerate through the MdiParent Controls collection. Once you find the MdiClient control, you can set its BackgroundImage property to whatever you want.
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Dave Kreskowiak+5 Right on target, Dave, and you reminded me of when ... several years ago ... I did some stuff with MDI (yuck), and I went back today, and took a look at the MdiClient component that is created when you set a Form's IsMdiContainer Property = true. The WinForms designers, probably having a bad hair day, set the Text and Name properties of MdiClient to an empty string, which means you can't do something like this to find it:
//
private MdiClient theMDIClientControl;
//
// note: don't need to recurse
Control[] potentialMDIClientControls = this.Controls.Find("MdiClient", false);
//
if (potentialMDIClientControls.Length > 0) theMDIClientControl = potentialMDIClientControls[0] as MdiClient;So, as you said, you gotta iterate/enumerate over the Controls collection of the Form.
"Last year I went fishing with Salvador Dali. He was using a dotted line. He caught every other fish." Steven Wright
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And yet neither of you are displaying an alternative that is better?
I'm not in the spoon feeding business, I did provide the two keywords that exist for dealing elegantly with such situations. So if you want to learn something, look them up and read the reference material. :|
Luc Pattyn [My Articles] Nil Volentibus Arduum
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And yet neither of you are displaying an alternative that is better?
Apparently you haven't been reading the posts. You also apparently won't be happy until you see actual code:
private void MdiClientExample()
{
foreach (Control c in this.Controls)
{
if (c is MdiClient)
{
MdiClient mc = (MdiClient)c;
...
}
}
}Are you happy now? Oh, and by the way, I don't consider this production quality code either. It's just cleaner than the example Microsoft gave. And if you're going to critisize us, you might want to start by creating your own code samples instead of lifting and posting others as your own work.
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Dave Kreskowiak -
I'm not in the spoon feeding business, I did provide the two keywords that exist for dealing elegantly with such situations. So if you want to learn something, look them up and read the reference material. :|
Luc Pattyn [My Articles] Nil Volentibus Arduum
So sorry you don't feel like trying to answer the ops question with something less cryptic. Seems forums just aren't as helpful as they used to be. Since you feel you are such an expert that you you don't need to provide examples my opinion, for what it's worth is that you are no help at all and shouldn't even be posting.
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So sorry you don't feel like trying to answer the ops question with something less cryptic. Seems forums just aren't as helpful as they used to be. Since you feel you are such an expert that you you don't need to provide examples my opinion, for what it's worth is that you are no help at all and shouldn't even be posting.
Yeah, right. A couple of Code Project MVP's aren't very helpful at all. The pile of 5-voted responses to questions just doesn't offer up any evidence at all of us being helpful. I'm not in the spoon-feed business either. There are just WAY too many very basic concept questions being asked that are very easily answered simply by typing the question into Google. I'd rather have someone learn how to do research themselves than just keep asking question after question about very basic topics.
A guide to posting questions on CodeProject[^]
Dave Kreskowiak -
Yeah, right. A couple of Code Project MVP's aren't very helpful at all. The pile of 5-voted responses to questions just doesn't offer up any evidence at all of us being helpful. I'm not in the spoon-feed business either. There are just WAY too many very basic concept questions being asked that are very easily answered simply by typing the question into Google. I'd rather have someone learn how to do research themselves than just keep asking question after question about very basic topics.
A guide to posting questions on CodeProject[^]
Dave KreskowiakActually Most everyone I know searches for the answers before hitting a forum with a question. Personally in my opinion it's more professional to offer assistance with a basic code example in the hopes the op learns something in the process. All anyone is learning from your responses is not to ask you for help.
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+5 Right on target, Dave, and you reminded me of when ... several years ago ... I did some stuff with MDI (yuck), and I went back today, and took a look at the MdiClient component that is created when you set a Form's IsMdiContainer Property = true. The WinForms designers, probably having a bad hair day, set the Text and Name properties of MdiClient to an empty string, which means you can't do something like this to find it:
//
private MdiClient theMDIClientControl;
//
// note: don't need to recurse
Control[] potentialMDIClientControls = this.Controls.Find("MdiClient", false);
//
if (potentialMDIClientControls.Length > 0) theMDIClientControl = potentialMDIClientControls[0] as MdiClient;So, as you said, you gotta iterate/enumerate over the Controls collection of the Form.
"Last year I went fishing with Salvador Dali. He was using a dotted line. He caught every other fish." Steven Wright
Very true. I found the lack of a name a little annoying at first, but I now prefer to find it by type. You really can't change the type at all, but the name can be changed breaking existing code.
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Dave Kreskowiak -
And yet neither of you are displaying an alternative that is better?
Alisaunder wrote:
And yet neither of you are displaying an alternative that is better?
I think the absence of code here is not the result of any 'negative intention:' It's just obvious that the best practice here is to enumerate the controls on the Form [1], test each one using the 'Is operator, and, when the MdiClient Control is found, then cast it from Type Control back to its 'native Type, 'MdiClient ... at which point you can have your way with it.
//
// assume you have loaded a valid image from an embedded resource
// into the variable of Type Bitmap named 'mdiBackGround'
//
private MdiClient theMDIClientControl;
//
foreach (Control theControl in this.Controls) [2]
{
if (theControl is MdiClient)
{
theMDIClientControl = theControl as MdiClient;
break;
}
}if (theMDIClientControl != null) theMDIClientControl.BackgroundImage = mdiBackGround;
[1] see my response to Dave K. above[^] confirming why it is absolutely necessary to enumerate the Controls on the Form. [2] Seems a reasonable assumption the MdiClient Control will always be in the top-level Form Control Collection: hence no need for a recursive search
"Last year I went fishing with Salvador Dali. He was using a dotted line. He caught every other fish." Steven Wright
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Apparently you haven't been reading the posts. You also apparently won't be happy until you see actual code:
private void MdiClientExample()
{
foreach (Control c in this.Controls)
{
if (c is MdiClient)
{
MdiClient mc = (MdiClient)c;
...
}
}
}Are you happy now? Oh, and by the way, I don't consider this production quality code either. It's just cleaner than the example Microsoft gave. And if you're going to critisize us, you might want to start by creating your own code samples instead of lifting and posting others as your own work.
A guide to posting questions on CodeProject[^]
Dave KreskowiakFunny, I have a feeling you weren't taught with original code either. This is another example of someone thinking the op should be equally as skilled as the person responding. If you don't feel like spoon feeding you shouldn't be offering assistance all you do is add to the confusion.
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Alisaunder wrote:
And yet neither of you are displaying an alternative that is better?
I think the absence of code here is not the result of any 'negative intention:' It's just obvious that the best practice here is to enumerate the controls on the Form [1], test each one using the 'Is operator, and, when the MdiClient Control is found, then cast it from Type Control back to its 'native Type, 'MdiClient ... at which point you can have your way with it.
//
// assume you have loaded a valid image from an embedded resource
// into the variable of Type Bitmap named 'mdiBackGround'
//
private MdiClient theMDIClientControl;
//
foreach (Control theControl in this.Controls) [2]
{
if (theControl is MdiClient)
{
theMDIClientControl = theControl as MdiClient;
break;
}
}if (theMDIClientControl != null) theMDIClientControl.BackgroundImage = mdiBackGround;
[1] see my response to Dave K. above[^] confirming why it is absolutely necessary to enumerate the Controls on the Form. [2] Seems a reasonable assumption the MdiClient Control will always be in the top-level Form Control Collection: hence no need for a recursive search
"Last year I went fishing with Salvador Dali. He was using a dotted line. He caught every other fish." Steven Wright
And in some rare cases it may not be in the top-level Form. Also adding Try and catch is error controlling which I don't care who you are is still considered good practice, otherwise you end up with crashing code that nobody can debug. Once you have a complete project you can remove The error handling code to streamline the application. But to say it's not good practice to include it is in my opinion really stupid and asking for trouble.
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The area of an MDI container window is covered by an MdiClient control; consequently, Form.BackColor and Form.BackgroundImage are ineffective. So How to set the background for this form.
I don't see where you problem is : if you cannot see the background of your MDI parent, it is because there is another object above it (its child) which is masking the main form. So, you can change the background color of the main form as you want, your change will be applied but you will not see it as there is still the same child object above it. Why don't you change the background color of the MdiClient control, so ? And, please, reserve the use of 'pre' tag for actual code.
No memory stick has been harmed during establishment of this signature.
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Actually Most everyone I know searches for the answers before hitting a forum with a question. Personally in my opinion it's more professional to offer assistance with a basic code example in the hopes the op learns something in the process. All anyone is learning from your responses is not to ask you for help.
Actually Most everyone I know searches for the answers before hitting a forum with a question. I don't agree with you : if you see the questions these days it is obvious that more and more people consider this forum as a 'code self-service'. Plenty of questions wouldn't have been told if the OP took time to search for it on CP or on Google first.
No memory stick has been harmed during establishment of this signature.
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Funny, I have a feeling you weren't taught with original code either. This is another example of someone thinking the op should be equally as skilled as the person responding. If you don't feel like spoon feeding you shouldn't be offering assistance all you do is add to the confusion.
Alisaunder wrote:
Funny, I have a feeling you weren't taught with original code either.
You're right. I'm self-taught over the span over 30+ years. When I was learning most of my stuff, there was no internet, so I was pretty much on my own, reading as much as I could.
Alisaunder wrote:
This is another example of someone thinking the op should be equally as skilled as the person responding.
With coding skills, not at all. But the research skills and the ability to teach yourself something new? Oh, yeah. Those are basic skills you learn in school and apply to the coding job every day. If you want someone to spoon-feed you stuff all the time, you're not going to last very long. And there are a TON of people who come here looking for the spoon. I give enough information to the OP so they can Google the problem themselves. In my humble opinion, new coders today have it much easier than I did learning this stuff.
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Dave Kreskowiak -
And in some rare cases it may not be in the top-level Form. Also adding Try and catch is error controlling which I don't care who you are is still considered good practice, otherwise you end up with crashing code that nobody can debug. Once you have a complete project you can remove The error handling code to streamline the application. But to say it's not good practice to include it is in my opinion really stupid and asking for trouble.
Alisaunder wrote:
Also adding Try and catch is error controlling which I don't care who you are is still considered good practice
Only if used appropriately. If this little block is coded up correctly, you won't have a need for a try/catch block at all. If I had to use a try/catch block, it wouldn't be in the manner than you copied from MSDN. It would have been outside the foreach or even in the caller and not this method and still used the if statement to test the control type.
A guide to posting questions on CodeProject[^]
Dave Kreskowiak