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Subject:
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Access cell in DataGrid - wrong casting?
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Posted By:
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drasko
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Post Date:
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12/18/2003 3:09:21 AM
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Hi all,
In my DataGrid1 I want to read one cell (data type int from database) and put it's value in the TextBox1 control.
private void DataGrid1_UpdateCommand(object source,
System.Web.UI.WebControls.DataGridCommandEventArgs e)
{....
TextBox1.Text = (Convert.ToInt64((e.Item.Cells[1].Controls[0]))).ToString();
....
}
I got run time error mesage : "Specified cast is not valid."
Can anyone tell me how to do this casting?
Thanks,
Nenad
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Reply By:
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planoie
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Reply Date:
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12/18/2003 9:14:06 AM
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e.Item.Cells[1].Controls[0] will return you the first control in cell 1. Usually you need to convert that to something explicitly so you can access a property value for that control:
TextBox1.Text = CType(e.Item.Cells[1].Controls[0], TextBox).Text;
However, if you are attempting to just get the value that's in the cell, you can just access the "Text" property of that cell:
e.Item.Cells[1].Text
The method you show here looks like the update handler for the grid so I would believe that you need the first suggestion unless the cell in question is in a readonly column.
When dealing with data grids, you must remember that after the data has been dumped to the grid, all the datatypes are as good as gone. Everything is a string in the grid. So you will always have to convert from a string back into the datatype you want.
Peter
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Work smarter, not harder.
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Reply By:
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drasko
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Reply Date:
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12/19/2003 8:12:13 AM
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Yes you are right I need the first example, I tried with this:
TextBox1.Text = ((TextBox)(e.Item.Cells[4].Controls[0])).Text;
but I still get the same error: Specified cast is not valid ???
Second example works with readonly cols like you said.
I have to solve this urgent
Thanks for your advice
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Reply By:
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planoie
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Reply Date:
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12/19/2003 9:30:29 AM
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Are you sure you have the right cell index? That index should match based on the columns in the "columns" area of the markup. Do you have any non-visible columns? You must count all columns.
Paste your datagrid markup if you are still having a problem.
Peter
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Work smarter, not harder.
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Reply By:
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drasko
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Reply Date:
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12/22/2003 3:45:34 AM
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Finally solution:
TextBox1.Text = ((TextBox)(e.Item.Cells[1].FindControl("txtBox1"))).Text;
because Cells[1] belongs TemplateColumn, and
markup:
<EditItemTemplate>
<asp:TextBox ID="txtBox1" BackColor=#ffcccc Width=50 runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.Kolicina") %>'>
</asp:TextBox>
</EditItemTemplate>
Thank you Peter you really helped me,
Nenad
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