How to set values ​​to custom DataGridBound column in WPF

Question

Since it is not possible to insert values ​​into a DataGridTemplateColumn. I found some suggestions for creating my own column class derived from a DataGridBoundColumn. The example below adds a DatePicker to a column without using a template.

However, this example does not allow me to manually set the value using DatePicker, and I'm not sure why. I think there is something with a binding. It will load the date values ​​that I bind to them initially, so that it is halfway there.

Interestingly, with some other helper classes, I can also insert dates that were origianl's target. I just didn’t want to break anything. :-)

Any ideas on how to choose the selected datepicker value correctly?

class MyDateColumn : DataGridBoundColumn 
{
    public string DateFormat { get; set; }
    protected override void CancelCellEdit(FrameworkElement editingElement, object uneditedValue)
    {
        DatePicker dp = editingElement as DatePicker;
        if (dp != null)
        {
            dp.SelectedDate = DateTime.Parse(uneditedValue.ToString());
        }
    }
    protected override FrameworkElement GenerateEditingElement(DataGridCell cell, object dataItem)
    {
        DatePicker dp = new DatePicker();
        Binding b = new Binding();
        Binding bb = this.Binding as Binding;
        b.Path = bb.Path;
        b.Source = DatePicker.SelectedDateProperty;
        if (DateFormat != null)
        {
            DateTimeConverter dtc = new DateTimeConverter();
            b.Converter = dtc;
            b.ConverterParameter = DateFormat;
        }
        dp.SetBinding(DatePicker.SelectedDateProperty, this.Binding);

        return dp;
    }

    protected override FrameworkElement GenerateElement(DataGridCell cell, object dataItem)
    {
        TextBlock txt = new TextBlock();
        Binding b = new Binding();
        Binding bb = this.Binding as Binding;
        b.Path = bb.Path;
        b.Source = cell.DataContext;

        if (DateFormat != null)
        {
            DateTimeConverter dtc = new DateTimeConverter();
            b.Converter = dtc;
            b.ConverterParameter = DateFormat;
        }
        txt.SetBinding(TextBlock.TextProperty, this.Binding);
        return txt;
    }

    protected override object PrepareCellForEdit(FrameworkElement editingElement, RoutedEventArgs editingEventArgs)
    {
        DatePicker dp = editingElement as DatePicker;
        if (dp != null)
        {
            DateTime? dt = dp.SelectedDate;
            if (dt.HasValue)
                return dt.Value;
        }
        return DateTime.Today;
    }

    protected override bool CommitCellEdit(FrameworkElement editingElement)
    {
        DatePicker dp = editingElement as DatePicker;
        dp.SelectedDate = DateTime.Today.AddYears(1);

        return true;
        //return base.CommitCellEdit(editingElement);
    }
}

Answer 1

CommitCellEdit()...

    protected override bool CommitCellEdit(FrameworkElement editingElement)
    {
        DatePicker dp = editingElement as DatePicker;
        DateTime dt;
        try
        {
            dt = Convert.ToDateTime(dp.Text);
            dp.SelectedDate = dt;
        }
        catch (FormatException)
        {
            dp.Text = String.Empty;
        }


        BindingExpression binding = editingElement.GetBindingExpression(DatePicker.SelectedDateProperty);
        if (binding != null)
            binding.UpdateSource();
        return true;
        //return base.CommitCellEdit(editingElement);
    }

...

http://leeontech.wordpress.com/2009/01/21/creating-datagriddatecolumn-for-datagrid/#comment-1033

, !

Answer 2

. 1 , DataGridTemplateColumn. , . BindingPath, , . , INotifyPropertyChanged. .

:

using System.Reflection;
using Microsoft.Windows.Controls;

namespace Bartosz.Wojtowicz.Wpf
{
    public class PastableDataGridTemplateColumn : DataGridTemplateColumn
    {
        public string BindingPath { get; set; }

        public override void OnPastingCellClipboardContent(object item, object cellContent)
        {
            if (item != null)
            {
                PropertyInfo propertyInfo = item.GetType().GetProperty(BindingPath);
                if (propertyInfo != null)
                {
                    propertyInfo.SetValue(item, cellContent, null);
                }
            }
        }
    }
}

xaml:

 <local:PastableDataGridTemplateColumn Header="Value" BindingPath="ValueView" ClipboardContentBinding="{Binding ValueView}" >
  <local:PastableDataGridTemplateColumn.CellTemplate >
    <DataTemplate>
      <!-- your template ... -->
    </DataTemplate>
  </local:PastableDataGridTemplateColumn.CellTemplate>
  <local:PastableDataGridTemplateColumn.CellEditingTemplate>
    <DataTemplate>
      <!-- your template ... -->
    </DataTemplate>
  </local:PastableDataGridTemplateColumn.CellEditingTemplate>
</local:PastableDataGridTemplateColumn>