CODEWITHSUNDEEP
datagridresizewpftoolkit
skylap
skylap

Reputation: 21

WPF DataGrid window resize does not resize DataGridColumns

I have a WPF DataGrid (from the WPFToolkit package) like the following in my application.

<Controls:DataGrid>
            <Controls:DataGrid.Columns>
                <Controls:DataGridTextColumn Width="1*" Binding="{Binding Path=Column1}" Header="Column 1" />
                <Controls:DataGridTextColumn Width="1*" Binding="{Binding Path=Column2}" Header="Column 2" />
                <Controls:DataGridTextColumn Width="1*" Binding="{Binding Path=Column3}" Header="Column 3" />
    </Controls:DataGrid.Columns>
</Controls:DataGrid>

The column width should be automatically adjusted such that all three columns fill the width of the grid, so I set Width="1*" on every column. I encountered two problems with this approach.

  1. When the ItemsSource of the DataGrid is null or an empty List, the columns won't size to fit the width of the grid but have a fixed width of about 20 pixel. Please see the following picture: http://img169.imageshack.us/img169/3139/initialcolumnwidth.png
  2. When I maximize the application window, the columns won't adapt their size but keep their initial size. See the following picture: http://img88.imageshack.us/img88/9362/columnwidthaftermaximiz.png
  3. When I resize the application window with the mouse, the columns won't resize.

I was able to solve problem #3 by deriving a sub class from DataGrid and override the DataGrid's OnRenderSizeChanged method as follows.

protected override void OnRenderSizeChanged(SizeChangedInfo sizeInfo)
{
    base.OnRenderSizeChanged(sizeInfo);
    foreach (var column in Columns)
    {
        var tmp = column.GetValue(DataGridColumn.WidthProperty);
        column.ClearValue(DataGridColumn.WidthProperty);
        column.SetValue(DataGridColumn.WidthProperty, tmp);
    }
}

Unfortunately this does not solve problems #1 and #2. How can I get rid of them?

Upvotes: 2

Views: 4866

Answers (4)

Svetozar Stefanov
Svetozar Stefanov

Reputation: 71

All DataGridTextColumn has a default MinWidth prperty set to 20. So, if you want to control width after resizing from max to min you have to specify this value yourself. My proposal is: 

    <DataGridTextColumn Header="Perfect&#x0a;column" Binding="{Binding SomeMember}" MinWidth="120" Width="120*"/>

Upvotes: 0

Bach Dao
Bach Dao

Reputation: 21

I have exactly the same problem as you but instead of listening to RenderSizeChanged, I listened to the SizeChanged event and it accounts for all of your situations.

dataGrid.SizeChanged += (sender_, arg_) =>
        {
          foreach (var dataGridColumn in dataGrid.Columns)
          {
            DataGridLength dataGridLength = dataGridColumn.Width;
            dataGridColumn.ClearValue(DataGridColumn.WidthProperty);
            dataGridColumn.Width = dataGridLength;
          }
        };

Upvotes: 2

nanobar
nanobar

Reputation: 66445

The following override fixes the size problem for the width growing bigger including maximize. But still not the restore size problem.

protected override void OnChildDesiredSizeChanged(UIElement e)
{
    base.OnChildDesiredSizeChanged(e);

    if (e.FindChild<DataGrid>() != null)
    {
        foreach (var column in dataGridMain.Columns)
        {
            var tmp = column.GetValue(DataGridColumn.WidthProperty);
            column.ClearValue(DataGridColumn.WidthProperty);
            column.SetValue(DataGridColumn.WidthProperty, tmp);
        }
    }
}

PS this problem only arose for me when I defined a GroupStyle template for the DataGrid, so it seems like a bug.

Upvotes: 0

Subha Basu
Subha Basu

Reputation: 1

I have also faced the same problem as you stated. I searched a bit in the internet, and probably find a solution. The solution actually works for me properly. Set the * value from C# code. Here is the code snippet,

dg.Coulmns[0].Width = new DataGridLength(1.0, DatGridLengthUnitType.Star);

It will set the 0th column's width to *. Don't forget to remove the Width="1**" from the XAML page.

Enjoy Guru.

Upvotes: 0

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