CODEWITHSUNDEEP
c#asp.netdatagrid
Tom Robinson
Tom Robinson

Reputation: 8508

How can I programmatically insert an additional row into an ASP.NET DataGrid?

I would like to programmatically insert additional rows into a DataGrid (to act as subheadings). I have followed a number of articles online (namely option 3 from http://aspalliance.com/723) but they all result in the row being displayed correctly, but with no contents.

Here is the important part of the code I'm using:

private void MyDataGrid_ItemCreated(object sender, DataGridItemEventArgs e)
{

    // This method will create a subheading row if needed
    if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
    {
        // TableCell
        TableCell tc = new TableCell();
        tc.Controls.Add(new LiteralControl("foo"));
        tc.ColumnSpan = e.Item.Cells.Count;

        // DataGridItem
        DataGridItem di = new DataGridItem(e.Item.ItemIndex + 1, 0, ListItemType.Item);
        di.Height = new Unit(100, UnitType.Pixel);
        di.CssClass = "testClass";
        di.Controls.Add(tc);

        // DataGrid Table
        DataGrid dg = (DataGrid)sender;
        Table childTable = (Table)dg.Controls[0];
        childTable.Rows.Add(di);
    }      

}

This results in the following markup being generated in the correct place, but without the LiteralControl("foo")

<tr class="testClass" style="height:100px;">
</tr>

I would like to use this approach rather than manipulating the datasource itself. What could be going wrong?

Upvotes: 0

Views: 2825

Answers (2)

Tom Robinson
Tom Robinson

Reputation: 8508

Problem solved - somewhere in the 2500 lines of existing code-behind, something was hiding the first column, effectively removing my addition. Something to watch out for if anyone else has similar problems.

Edit - Here's the code I've written to get round the problem in a reasonably generic way:

private void InsertDataGridRow(DataGrid dataGrid, int index, TableCell tc)
{
    DataGridItem di = new DataGridItem(index, 0, ListItemType.Item);

    // Check which columns are visible
    bool foundFirstVisibleColumn = false;
    int numberOfVisibleColumns = 0;
    foreach (DataGridColumn column in dataGrid.Columns)
    {
        if (column.Visible == true)
        {
            numberOfVisibleColumns++;
            foundFirstVisibleColumn = true;
        }

        // Add dummy columns in the columns that are hidden
        if (!foundFirstVisibleColumn)
        {
            di.Cells.Add(new TableCell());
        }

    }

    tc.ColumnSpan = numberOfVisibleColumns;
    di.Cells.Add(tc);
    Table t = (Table)dataGrid.Controls[0];
    t.Rows.Add(di);
}

And the above can be called something like this:

private void MyDataGrid_ItemCreated(object sender, DataGridItemEventArgs e)
{
    // This method will create a subheading row if needed
    if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
    {
        TableCell tc = new TableCell();
        tc.Controls.Add(new LiteralControl("foo"));

        InsertDataGridRow(
            (DataGrid)sender,
            e.Item.ItemIndex + 1,
            tc);
    }      

}

Upvotes: 2

Adam Ralph
Adam Ralph

Reputation: 29956

I just tried an isolated example using the code you posted and it works just fine. It must be something to do with either the config of your DataGrid or something elsewhere in your code.

Upvotes: 1

Related Questions