How to Bind CurrentCell in WPF datagrid using MVVM pattern

Question

I'm learning WPF MVVM pattern. I'm stuck in Binding CurrentCell of datagrid. Basically I need the row index and column index of current cell.

<DataGrid AutoGenerateColumns="True" 
          SelectionUnit="Cell" 
          CanUserDeleteRows="True" 
          ItemsSource="{Binding Results}" 
          CurrentCell="{Binding CellInfo}" 
          Height="282" 
          HorizontalAlignment="Left" 
          Margin="12,88,0,0" 
          Name="dataGrid1" 
          VerticalAlignment="Top" 
          Width="558" 
          SelectionMode="Single">

Here is my ViewModel

private User procedureName = new User();

public  DataGridCell   CellInfo
{
    get { return procedureName.CellInfo; }
    //set
    //{
    //    procedureName.CellInfo = value;
    //    OnPropertyChanged("CellInfo");
    //}
}

Here is my Model

private DataGridCell cellInfo;

public DataGridCell CellInfo
{
    get { return cellInfo; }
    //set
    //{
    //    cellInfo = value;
    //    OnPropertyChanged("CellInfo");
    //}
}

And in my ViewModel CellInfo is always null. I am not able to get the value from the currentcell in datagrid. Please let me know a way to getCurrentCell in the ViewModel.

if (CellInfo != null)
{
    MessageBox.Show("Value is" + CellInfo.Column.DisplayIndex.ToString());
}

Answer 1

After having a quick poke-around I've noticed a very simple solution to your problem.

First of all there's two problems rather then one here. You cannot bind a CellInfo of a type DataGridCell, it needs to be DataGridCellInfo as xaml cannot convert it on its own.

Secondly in your xaml you will need to add Mode=OneWayToSource or Mode=TwoWay to your CellInfo binding.

Here is a rough example semi-related to your original code

XAML

<DataGrid AutoGenerateColumns="True"
          SelectionUnit="Cell"
          SelectionMode="Single"
          Height="250" Width="525" 
          ItemsSource="{Binding Results}"
          CurrentCell="{Binding CellInfo, Mode=OneWayToSource}"/>

VM

private DataGridCellInfo _cellInfo;
public DataGridCellInfo CellInfo
{
    get { return _cellInfo; }
    set
    {
        _cellInfo = value;
        OnPropertyChanged("CellInfo");
        MessageBox.Show(string.Format("Column: {0}",
                        _cellInfo.Column.DisplayIndex != null ? _cellInfo.Column.DisplayIndex.ToString() : "Index out of range!"));
    }
}

Just a small tip - if you debug your app and look at the Output window it actually tells you if there is any troubles with your bindings.

Hope this helps!

K.