Maching the row in a datagrid to a row in a DataTable
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I have a dataTable set as the Datasource of of a dataGrid via a DataView. The Table contains an ID field and a Description field, of which only the Description is displayed in the grid. I want to be able to programatically retrive the ID from the DataTable based on a row in in the DataGrid. How can I do this, even if the grid has been sorted? Thanks Stephen.
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I have a dataTable set as the Datasource of of a dataGrid via a DataView. The Table contains an ID field and a Description field, of which only the Description is displayed in the grid. I want to be able to programatically retrive the ID from the DataTable based on a row in in the DataGrid. How can I do this, even if the grid has been sorted? Thanks Stephen.
If the ID is still bound to a column which is marked as not visible then you should still be able to access it as if it was visible. Paul
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If the ID is still bound to a column which is marked as not visible then you should still be able to access it as if it was visible. Paul
Thanks for the quick reply, had over looked that simple idea! Anyway, I would stil like to be able to get back to the row in the dataTable, is it possible? Thanks Stephen.
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Thanks for the quick reply, had over looked that simple idea! Anyway, I would stil like to be able to get back to the row in the dataTable, is it possible? Thanks Stephen.
Not sure exactly what you mean. Can you expand on the question a little... give an example if possible. Paul
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Not sure exactly what you mean. Can you expand on the question a little... give an example if possible. Paul
OK, say I had code that looked like this..
DataSet ds = GetMyDataSet () ; DataTable dt = ds.Tables["Results"] ; DataView dv = new DataView (dt) ; dv.AllowNew = false ; dataGrid1.DataSource = dv ;And somewhere else I want to delete the current row in response to a button click from the tool bar. I could do..DataView dv = (DataView )dataGrid1.DataSource ; DataTable dt = dv.Table ; dt.Rows[dg.CurrentCell.RowNumber].Delete ;But if the grid has been sorted by using the column headers this will no longer work as the grid row number no longer matches the row number in the dataTable. What I would like to do is find a way to go from a row in the datagrid to the row in the datasource. The delete is just an example, it is the row mapping that is realy of intreast to me. Thanks Stephen. -
OK, say I had code that looked like this..
DataSet ds = GetMyDataSet () ; DataTable dt = ds.Tables["Results"] ; DataView dv = new DataView (dt) ; dv.AllowNew = false ; dataGrid1.DataSource = dv ;And somewhere else I want to delete the current row in response to a button click from the tool bar. I could do..DataView dv = (DataView )dataGrid1.DataSource ; DataTable dt = dv.Table ; dt.Rows[dg.CurrentCell.RowNumber].Delete ;But if the grid has been sorted by using the column headers this will no longer work as the grid row number no longer matches the row number in the dataTable. What I would like to do is find a way to go from a row in the datagrid to the row in the datasource. The delete is just an example, it is the row mapping that is realy of intreast to me. Thanks Stephen.You could search through the DataTable for the record with the same ID column. But I feel you're missing some of the power of DataSets. Try Adding a DataSet design to your project, define the layout of your dataset and set the ID as a Primary key. This generates a DataSet-derived class with a lot more power, exposing methods like Search() or FindByXXX() [where XXX is the Primary Key name]. If you then want to duplicate your changes in some sort of database, take a good look at DataAdapters. None of this is simple stuff when you first come to look at it but once you've done it a couple of times, you can start knocking them together in no time. Trust me, it's worth the initial effort. Paul
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You could search through the DataTable for the record with the same ID column. But I feel you're missing some of the power of DataSets. Try Adding a DataSet design to your project, define the layout of your dataset and set the ID as a Primary key. This generates a DataSet-derived class with a lot more power, exposing methods like Search() or FindByXXX() [where XXX is the Primary Key name]. If you then want to duplicate your changes in some sort of database, take a good look at DataAdapters. None of this is simple stuff when you first come to look at it but once you've done it a couple of times, you can start knocking them together in no time. Trust me, it's worth the initial effort. Paul
I kept the example short in an attempt to get the point of my question cross, is there a way to map the selected row in a datagrid to the related row in the underlying dataset. I am unable to use DataAdapters as the original datasource is not supported by ADO.NET I could use the Hidden ID column and search by Primary key method to find the row in the dataset, it just seems wrong when there must be a direct link back to the row in the dataset somewhere. The grid must know what row it is displaying to be able to update when the row is changed! Also, on a related note, I want to do the same thing in DataGridColumnStyle derived class that uses columns in the DataTable that are not displayed in the grid. In this the edit and comit methods provide a row number in the datagrid, but I am at a loss on how to map that back into the dataset. Stephen.
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I kept the example short in an attempt to get the point of my question cross, is there a way to map the selected row in a datagrid to the related row in the underlying dataset. I am unable to use DataAdapters as the original datasource is not supported by ADO.NET I could use the Hidden ID column and search by Primary key method to find the row in the dataset, it just seems wrong when there must be a direct link back to the row in the dataset somewhere. The grid must know what row it is displaying to be able to update when the row is changed! Also, on a related note, I want to do the same thing in DataGridColumnStyle derived class that uses columns in the DataTable that are not displayed in the grid. In this the edit and comit methods provide a row number in the datagrid, but I am at a loss on how to map that back into the dataset. Stephen.
stephen woolhead wrote: I could use the Hidden ID column and search by Primary key method to find the row in the dataset, it just seems wrong when there must be a direct link back to the row in the dataset somewhere. There isn't, I'm afraid. DataSets and DataGrids are two completely unrelated things, Daatabinding just allows you to link them. You have to create your own link between records like that. stephen woolhead wrote: I am unable to use DataAdapters as the original datasource is not supported by ADO.NET Not even using ODBC.NET[^]? stephen woolhead wrote: Also, on a related note, I want to do the same thing in DataGridColumnStyle derived class that uses columns in the DataTable that are not displayed in the grid. In this the edit and comit methods provide a row number in the datagrid, but I am at a loss on how to map that back into the dataset. Through a primary key again, I suspect. You're stepping a little beyond my range of experience here though :) Paul
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stephen woolhead wrote: I could use the Hidden ID column and search by Primary key method to find the row in the dataset, it just seems wrong when there must be a direct link back to the row in the dataset somewhere. There isn't, I'm afraid. DataSets and DataGrids are two completely unrelated things, Daatabinding just allows you to link them. You have to create your own link between records like that. stephen woolhead wrote: I am unable to use DataAdapters as the original datasource is not supported by ADO.NET Not even using ODBC.NET[^]? stephen woolhead wrote: Also, on a related note, I want to do the same thing in DataGridColumnStyle derived class that uses columns in the DataTable that are not displayed in the grid. In this the edit and comit methods provide a row number in the datagrid, but I am at a loss on how to map that back into the dataset. Through a primary key again, I suspect. You're stepping a little beyond my range of experience here though :) Paul
Paul Riley wrote: Not even using ODBC.NET[^]? I need to access a password protected Paradox table (not by choice :)), and as far as I know there is no way to do that with ODBC. So I have a Managed C++ dll that uses the BDE directly to build me a Dataset. Paul Riley wrote: stephen woolhead wrote: I could use the Hidden ID column and search by Primary key method to find the row in the dataset, it just seems wrong when there must be a direct link back to the row in the dataset somewhere. There isn't, I'm afraid. DataSets and DataGrids are two completely unrelated things, Daatabinding just allows you to link them. You have to create your own link between records like that. I have fianlly worked it out, looks something like this using the previous delete example...
BindingManagerBase cm = this.BindingContext[dg.DataSource] ; DataRowView drv = (DataRowView )cm.Current ; ((DataRow )drv.Row).Delete () ;I found this was a good link if you MSDN installed ms-help://MS.MSDNQTR.2002APR.1033/vbcon/html/vbconConsumersOfDataOnWindowsForms.htm[^] While there is no direct link between the dataSet and the DataGrid, there are container level objects that you can access that are looking after it for you. Anyway, thanks for all your replies, they really helped. Stephen. -
Paul Riley wrote: Not even using ODBC.NET[^]? I need to access a password protected Paradox table (not by choice :)), and as far as I know there is no way to do that with ODBC. So I have a Managed C++ dll that uses the BDE directly to build me a Dataset. Paul Riley wrote: stephen woolhead wrote: I could use the Hidden ID column and search by Primary key method to find the row in the dataset, it just seems wrong when there must be a direct link back to the row in the dataset somewhere. There isn't, I'm afraid. DataSets and DataGrids are two completely unrelated things, Daatabinding just allows you to link them. You have to create your own link between records like that. I have fianlly worked it out, looks something like this using the previous delete example...
BindingManagerBase cm = this.BindingContext[dg.DataSource] ; DataRowView drv = (DataRowView )cm.Current ; ((DataRow )drv.Row).Delete () ;I found this was a good link if you MSDN installed ms-help://MS.MSDNQTR.2002APR.1033/vbcon/html/vbconConsumersOfDataOnWindowsForms.htm[^] While there is no direct link between the dataSet and the DataGrid, there are container level objects that you can access that are looking after it for you. Anyway, thanks for all your replies, they really helped. Stephen.stephen woolhead wrote: I need to access a password protected Paradox table (not by choice ), and as far as I know there is no way to do that with ODBC. Ick! No idea, but I suspect you're right. stephen woolhead wrote: I have fianlly worked it out ...snip...While there is no direct link between the dataSet and the DataGrid, there are container level objects that you can access that are looking after it for you. I'm impressed. Didn't know such a thing existed, thanks. Glad to be of some help (if only pointing your mind in the right direction) and it seems I've learned something too :) Paul