如何捕获 DataGrid 列标题上的“单击”事件

Question

It appears that the DataGrid that comes with .NET 4 does not contain an event for both column and row header clicks. I want to receive events for the column header click as I want to provide my own sorting behaviour and turn off the default sorting, this is because my view-model is a paginated model that will only display 25/50/100 rows at a time, the default sorting will of-course sort the current page only.

Now I could create a new DataGridColumnHeader style which contains a clickable element and and set ColumnHeaderStyle , though this just seems like a pain as I'll have trouble figuring out things like which column it was that got clicked etc.

Anyone else come up against this and solved it?

Answer 1

The headers are just buttons. Like any button, you can register to the Click event to capture those clicks. Just set a style targeting DataGridColumnHeader and add a Click event handler. Then within the handler, you have access to the header directly via the sender . You could then get the Column associated with that header and other information associated with it.

<DataGrid>
    <DataGrid.Resources>
        <Style TargetType="DataGridColumnHeader">
            <EventSetter Event="Click" Handler="columnHeader_Click" />
        </Style>
    </DataGrid.Resources>
</DataGrid>

Then in the code:

private void columnHeader_Click(object sender, RoutedEventArgs e)
{
    var columnHeader = sender as DataGridColumnHeader;
    if (columnHeader != null)
    {
        // do stuff
    }
}

---

Looking further into the DataGrid , I noticed that there's a ColumnHeaderStyle property. I think it would be a better idea to apply the style through this property instead.

<DataGrid>
    <DataGrid.ColumnHeaderStyle>
        <Style TargetType="DataGridColumnHeader">
            <EventSetter Event="Click" Handler="columnHeader_Click" />
        </Style>
    </DataGrid.ColumnHeaderStyle>
</DataGrid>

Answer 2

It is also possible to do this programmatically :

using System.Windows.Controls.Primitives;

...

public TestWindow()
{
  if (TestDataGrid.ColumnHeaderStyle == null)
  {
    TestDataGrid.ColumnHeaderStyle = new Style(typeof(DataGridColumnHeader));
  }
  TestDataGrid.ColumnHeaderStyle.Setters.Add(new EventSetter(ButtonBase.ClickEvent,
       new RoutedEventHandler(TestDataGrid_HeaderRowClick)));
}


private void TestDataGrid_HeaderRowClick(object sender, RoutedEventArgs e)
{
  ...
}

Here the method "TestDataGrid_HeaderRowClick" is called, when the use clicks with the left mouse button into the header row.

Answer 3

After struggling for quite a long time, I got this full resolution.

In FormMain.Designer.cs, add handler (the second one):

    private void InitializeComponent()
    {
        ...
        this.TableOfBriefs.CellDoubleClick += new System.Windows.Forms.DataGridViewCellEventHandler(this.TableOfBriefs_CellContentClick);
        this.TableOfBriefs.ColumnHeaderMouseClick += new DataGridViewCellMouseEventHandler(this.TableOfBriefs_HeaderClick);

In Forman.cs, add the method:

    private readonly Dictionary<string, bool> _columnName2Orders = new Dictionary<string, bool>();
    private const bool IsAscendingWhenFirstClicked = false;
    private void TableOfBriefs_HeaderClick(object sender, DataGridViewCellMouseEventArgs e)
    {
        if (!(sender is DataGridView dataGrid))
            throw new ArgumentException(@$"{sender} is not a {typeof(DataGridView)}.");

        var column = dataGrid.Columns[e.ColumnIndex];
        var propertyInfo = typeof(CciSingleFileResultBrief).GetProperty(column.Name);
        if (propertyInfo == null)
            throw new ArgumentException($@"There is no property named {column.Name} found in class {typeof(CciSingleFileResultBrief)}.");

        if (!_columnName2Orders.ContainsKey(propertyInfo.Name))
            _columnName2Orders.Add(propertyInfo.Name, IsAscendingWhenFirstClicked);
        _columnName2Orders[propertyInfo.Name] = !_columnName2Orders[propertyInfo.Name];

        var isAscending = _columnName2Orders[propertyInfo.Name];
        var briefs = isAscending ? _briefs.OrderByDescending(i => propertyInfo.GetValue(i)).ToList()
                : _briefs.OrderBy(i => propertyInfo.GetValue(i)).ToList();
        TableOfBriefs.DataSource = briefs;
    }