Empty DataGrid renders funny when custom columns added

09-01-2008 6:04 PM |

I'm working on a demo project that involves a datagrid.  When AutoGenerateColumns is set to true the datagrid looks fine whether ItemsSource is set to null or to real data.  However when I set AutoGenerateColumns to False and define custom columns, the grid only shows a partial border when ItemsSource is set to null.  Once I set ItemsSource to real data it looks fine again.  How can I get the empty grid to render normally -- i.e. have a full border not border on the left hand side and the right hand half of the border blanked out.

      <my:DataGrid Margin="8,283,51,87" AutoGenerateColumns="False" x:Name="ResultsGrid" >
        <my:DataGrid.Columns>
                <my:DataGridTextColumn
                    Header="Test Item 1"
                    DisplayMemberBinding="{Binding TestItem1}"/>
                <my:DataGridTextColumn
                    Header="Test Item 2"
                    DisplayMemberBinding="{Binding TestItem2}"/>
        </my:DataGrid.Columns>
      </my:DataGrid>

Re: Empty DataGrid renders funny when custom columns added

09-03-2008 3:28 AM |

Hello, this is by design for Beta 2. But in RTW, the behavior may change, so that even if your data source is empty, as long as you have defined the columns, the columns will be displayed, just there're 0 rows. In Beta 2, the only workaround I can think is to create a fake data source which contains one item, and in the LoadingRow event handler, you hide the first row after data is bound.

private bool fakeData;

List<Data> source = new List<Data>();
source.Add(new Data() { Text = "aaa" });
fakeData = true;
dg.ItemsSource = source;

private void dg_LoadingRow(object sender, DataGridRowEventArgs e)
{
if (fakeData)
{
e.Row.Visibility = Visibility.Collapsed;
}
}

Later when you have real data source, you set fakeData to false, or remove the LoadingRow event handler completely.

Re: Empty DataGrid renders funny when custom columns added

09-03-2008 8:07 PM |

The partial border is a bug in the Beta 2 template of the DataGrid.  This has been fixed for RTM.  In addition, Yi-Lun is correct, the RTM DataGrid will show the column headers even if you have no items to display.

Re: Re: Empty DataGrid renders funny when custom columns added

09-04-2008 7:23 AM |

I can confirm that, I have the same "bug/effect" in a project that i'm developing now.

Re: Re: Empty DataGrid renders funny when custom columns added

09-12-2008 11:44 PM |

The help you guys gave me above with DataGrid was incorporated into a step-by-step tutorial I wrote on how to build a datacentric silverlight web app that uses WCF and LINQ to submit and retreive data from a database.  You can check it out at my blog at http://http://www.silverlightwebapps.com/Tutorials.aspx.