对xaml中的第一列启用DataGrid排序

Question

I have a DataGrid in WPF with autogenerated columns.

How can I disable sorting functionality of all the rows except the first one which corresponds time in my Source.

I am following MVVM pattern and I know that CanUserSortColumns is disabling sorting for all the columns. I want to disable all but the first column.

Should I write trigger or interaction or something else? All the help is appreciated.

<DataGrid AutoGenerateColumns="True" 
        ItemsSource="{Binding MyDataTable}" 
        CanUserSortColumns="False">
</DataGrid>

Answer 1

I found this code snippet for you:

<my:DataGridTemplateColumn  SortMemberPath="CompleteDate" Header="Complete Date" CanUserSort="true">
            <my:DataGridTemplateColumn.CellTemplate >
                    <DataTemplate>
                        <TextBlock>
                            <TextBlock.Text>
                                <Binding Path="CompleteDate" ConverterCulture="en-GB" StringFormat="{}{0:MM/dd/yyyy}"/>
                            </TextBlock.Text>
                        </TextBlock>
                    </DataTemplate>
                </my:DataGridTemplateColumn.CellTemplate>
            </my:DataGridTemplateColumn>

Use the CanUserSort Property to define it's sortable-state column explicit. The SortMemberPath defines the Property you use for sorting. Hope this helps.

UPDATE: If you are using autogenerated columns you can't access them via xaml. So you need to access them in code File.

I'm not familiar with the xaml Grid but would expect something like:

//Bound Data here so that the Grid generate the columns

int i = 0;
foreach (DataColumn column in myGrid.ColumnCollection)
{
   if (i == 0)
      column.CanSortUser = true;
   else
      column.CanSortUser = false;

   i++;
}

The original Typenames can differ but something this way should be possible.

UPDATE-2

If you don't want to hurt the MVVM you can use this . There is described how to use Interfaces to access the code and stay independet with your view and viewmodel.

Answer 2

The problem is, that DataGridColumnHeader has the CanUserSort property as a local computed property. It can been set by manually generating the columns (what you don't want).

If it was a property with setter you could create a DataTrigger looking at TabIndex == 0 and set through Setter in xaml Style.

Your only chance by using AutoGeneratedColumns is the following:

<DataGrid AutoGenerateColumns="True" 
    ItemsSource="{Binding MyDataTable}" 
    CanUserSortColumns="True"
    AutoGeneratedColumns="DataGrid_OnAutoGeneratedColumns">
</DataGrid>

your codebehind:

private void DataGrid_OnAutoGeneratedColumns(object sender, EventArgs e)
{
    DataGrid dg = sender as DataGrid;
    if (dg == null) return;
    dg.Columns.ToList().Select((col, indx) => new {Col = col, Indx = indx}).ToList().ForEach(obj => obj.Col.CanUserSort = obj.Indx == 0);
}

This enables the first columns UserCanSort property and disables the others. This function is independend from your viewmodel and can been placed at your view.xaml.cs code behind file.

EDIT:

If you won't have any codebehind you can just do it by using your own DataGridControl .

MyDataGrid.cs

namespace YourNamespace {
    public class MyDataGrid : DataGrid
    {
        protected override void OnAutoGeneratedColumns(EventArgs e)
        {
            DataGrid dg = sender as DataGrid;
            if (dg == null) return;
            dg.Columns.ToList().Select((col, indx) => new {Col = col, Indx = indx}).ToList().ForEach(obj => obj.Col.CanUserSort = obj.Indx == 0);

            base.OnAutoGeneratedColumns(e);
        }
    }
}

your view:

<YourNamespace:MyDataGrid AutoGenerateColumns="True" 
    ItemsSource="{Binding MyDataTable}" 
    CanUserSortColumns="True">
</YourNamespace:MyDataGrid>

and you are done without a single line codebehind.