Question

I am using a WPF datagrid. I am providing a context menu for row-header and column-header. The code is as mentioned below:

MainWindow.xaml

<Window x:Class="WpfApplication10.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:cmd="clr-namespace:WpfApplication10"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <Grid.Resources>
        <Style TargetType="{x:Type DataGridColumnHeader}">
            <Setter Property="ContextMenu">
                <Setter.Value>
                    <ContextMenu>
                        <MenuItem Header="Insert Column Before" Command="cmd:ContextMenuCustomCommands.InsertColumnBeforeCommand" />
                        <MenuItem Header="Insert Column After" Command="cmd:ContextMenuCustomCommands.InsertColumnAfterCommand"/>
                    </ContextMenu>
                </Setter.Value>
            </Setter>
        </Style>
        <Style TargetType="{x:Type DataGridRowHeader}">
            <Setter Property="ContextMenu">
                <Setter.Value>
                    <ContextMenu>
                        <MenuItem Header="Delete" Command="Delete"/>
                    </ContextMenu>
                </Setter.Value>
            </Setter>
        </Style>
    </Grid.Resources>
    <Grid.CommandBindings>
        <CommandBinding Command="cmd:ContextMenuCustomCommands.InsertColumnBeforeCommand" CanExecute="InserColumnBefore_CanExecute" Executed="InserColumnBefore_Executed"/>
        <CommandBinding Command="cmd:ContextMenuCustomCommands.InsertColumnAfterCommand" CanExecute="InsertColumnAfter_CanExecute" Executed="InsertColumnAfter_Executed"/>
    </Grid.CommandBindings>
    <DataGrid x:Name="grdEmployee" ItemsSource="{Binding}" AutoGeneratingColumn="grdEmployee_AutoGeneratingColumn" LoadingRow="grdEmployee_LoadingRow" SelectionUnit="CellOrRowHeader">

    </DataGrid>
</Grid>

MainWindow.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Data;
using System.Data.SqlClient;

namespace WpfApplication10
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
{
    private SqlConnection empCon = null;
    private SqlCommand empCmd = null;
    private DataSet empDS = null;
    private SqlDataAdapter empAdap = null;
    private string query = "SELECT * FROM Employees";
    public MainWindow()
    {
        InitializeComponent();

        this.grdEmployee.ItemsSource = this.GetEmployeeData().DefaultView;
    }

    private DataTable GetEmployeeData()
    {
        try
        {
            empCon = new SqlConnection(Application.Current.Properties["connectionStr"].ToString());
            empCmd = new SqlCommand(query, empCon);
            empAdap = new SqlDataAdapter(empCmd);
            empDS = new DataSet();
            empAdap.Fill(empDS);
        }
        catch (SqlException sqlEx)
        {
        }
        finally
        {
            if (empCon != null)
                empCon.Dispose();

            if (empCmd != null)
                empCmd.Dispose();
        }

        if (empDS != null)
        {
            for (int count = 1; count <= empDS.Tables[0].Columns.Count; count++)
            {
                empDS.Tables[0].Columns[count - 1].ColumnName = Utility.ConvertNumber(count).ToString();
            }
            return empDS.Tables[0];
        }
        else
        {
            return null;
        }
    }

    private void grdEmployee_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
    {

    }

    private void grdEmployee_LoadingRow(object sender, DataGridRowEventArgs e)
    {
        e.Row.Header = (e.Row.GetIndex() + 1).ToString();
    }

    private void InserColumnBefore_CanExecute(object sender, CanExecuteRoutedEventArgs e)
    {
        e.CanExecute = true;
    }

    private void InserColumnBefore_Executed(object sender, ExecutedRoutedEventArgs e)
    {

    }

    private void InsertColumnAfter_CanExecute(object sender, CanExecuteRoutedEventArgs e)
    {
        e.CanExecute = true;
    }

    private void InsertColumnAfter_Executed(object sender, ExecutedRoutedEventArgs e)
    {

    }
    }

    public class Utility
{
    private static string chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

    public static string ConvertNumber(int number)
    {
        string result;
        number -= 1;
        int rest = number % 26;
        int q = number / 26;
        if (q == 0)
        {
            result = chars[rest].ToString();
        }
        else
        {
            result = ConvertNumber(q) + chars[rest];
        }
        return result;
    }
    }

public static class ContextMenuCustomCommands
{
    public static readonly RoutedUICommand InsertColumnBeforeCommand = new RoutedUICommand("Insert Column Before", "Insert Column Before", typeof(MainWindow));
    public static readonly RoutedUICommand InsertColumnAfterCommand = new RoutedUICommand("Insert Column After", "Insert Column After", typeof(MainWindow));
}
}

App.xaml.cs

using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Windows;

namespace WpfApplication10
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        public App()
    {
        string connectionStr = "Integrated Security=SSPI;Persist Security Info=False;Initial Catalog=Northwind;Data Source=(local);";
        Application.Current.Properties["connectionStr"] = connectionStr;
    }
}

}

The problem I am facing is: In the context menu when I click on the option given insert column, I need to find out from which column header the user has raised the event.

Answer 1

The ContextMenu.PlacementTarget will be the column header, you could hence bind the CommandParameter to that so you can use it in the command.

CommandParameter="{Binding PlacementTarget,
                           RelativeSource={RelativeSource AncestorType=ContextMenu}}"