passing selecteditems to a stored procedure from wpf datagrid through mvvm

Question

I implemented this already without using MVVM:

private void Del_btn_Click(object sender, RoutedEventArgs e)
{
    try
    {
        List<string> cid = new List<string>();
        foreach (DataRowView rw in Xgrid.SelectedItems)
        {

            cid.Add(rw[1].ToString());
            MessageBox.Show("Deleting " + rw[1].ToString());
        }

        foreach (string cq in cid)
        {
            SqlConnection con = new SqlConnection(str);

            con.Open();
            SqlCommand cmd = new SqlCommand("delete_prc", con);
            cmd.CommandType = CommandType.StoredProcedure;
            SqlParameter param1 = new SqlParameter();
            param1.ParameterName = "@Cid";
            param1.SqlDbType = SqlDbType.NVarChar;
            param1.Value = cq;
            cmd.Parameters.Add(param1);
            cmd.ExecuteNonQuery();
        }
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.ToString());
    }
}

Now I want to do this with MVVM.

I have customers.cs model class in which I have all the fields. Now I don't know how to bind the check box so I am able to do this.

Xaml code:

<DataGrid.RowHeaderTemplate>
    <DataTemplate>
        <Grid>
            <CheckBox   IsChecked="{Binding Path=ViewModelBase.CheckAll, 
                        Mode=TwoWay, UpdateSourceTrigger=PropertyChanged,
                        RelativeSource={RelativeSource FindAncestor,
                        AncestorType={x:Type DataGridRow}}}" Name="delete"/>
        </Grid>
    </DataTemplate>
</DataGrid.RowHeaderTemplate>

<DataGrid.Columns>
    <DataGridTextColumn Header="rowNo." Width="60" Binding="{Binding RowNumber}" IsReadOnly="True">
        <DataGridTextColumn.ElementStyle>
            <Style TargetType="TextBlock">
                <Setter Property="HorizontalAlignment" Value="Center" />
            </Style>
        </DataGridTextColumn.ElementStyle>
    </DataGridTextColumn>
    <DataGridTextColumn Header="CustomerID" Width="80" Binding="{Binding CustomerID}" IsReadOnly="True"></DataGridTextColumn>
    <DataGridTextColumn Header="CompanyName" Width="100" Binding="{Binding CompanyName}"></DataGridTextColumn>
    <DataGridTextColumn Header="ContactName" Width="100" Binding="{Binding ContactName}"></DataGridTextColumn>
    <DataGridTextColumn Header="ContactTitle" Width="100" Binding="{Binding ContactTitle}"></DataGridTextColumn>
    <DataGridTextColumn Header="Address" Width="80" Binding="{Binding Address}"></DataGridTextColumn>
    <DataGridTextColumn Header="City" Width="100" Binding="{Binding City}"></DataGridTextColumn>
    <DataGridTextColumn Header="Region" Width="80" Binding="{Binding Region}"></DataGridTextColumn>
    <DataGridTextColumn Header="PostalCode" Width="100" Binding="{Binding PostalCode}"></DataGridTextColumn>
    <DataGridTextColumn Header="Country" Width="100" Binding="{Binding Country}"></DataGridTextColumn>
    <DataGridTextColumn Header="Phone" Width="100" Binding="{Binding Phone}"></DataGridTextColumn>
    <DataGridTextColumn Header="Fax" Width="100" Binding="{Binding Fax}"></DataGridTextColumn>

</DataGrid.Columns>

So how to integrate this with mvvm. please help me doing this.

I want to know what to define in my viewmodel class and what should be the binding path to do this.

Answer 1

In your DataGrid put a command like and you need to add

xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"

  <DataGrid HorizontalAlignment="Left" VerticalAlignment="Top" Height="103" Width="517">
        <i:Interaction.Triggers>
            <i:EventTrigger EventName="MouseDoubleClick">
                <i:InvokeCommandAction Command="{Binding GetItem}" CommandParameter="{Binding Header,ElementName=id}"/>
            </i:EventTrigger>
        </i:Interaction.Triggers>
   </DataGrid>

and access the Command in your ViewModel like this

  RelayCommand getitem;
    public RelayCommand GetItem
    {
        get
        {
            if(getitem == null)
            {
                getitem = new RelayCommand(p=>Executeyourcommand(p));
            }
            return getitem;
        }
    }


  void Executeyourcommand(object parameter)
    {
        // parameter is your CustomerID
       // do your work here
    }

your Command helper class

 public class RelayCommand : ICommand
{
    readonly Action<object> execute;
    readonly Predicate<object> canexecute;

    public RelayCommand(Action<object> execute)
        : this(execute, null)
    {

    }
    public RelayCommand(Action<object> Execute, Predicate<object> Canexecute)
    {
        if(Execute == null)
            throw new ArgumentNullException("execute");
        execute = Execute;
        canexecute = Canexecute;
    }
    public bool CanExecute(object parameter)
    {
        if(canexecute == null)
            return true;
        else
            return canexecute(parameter);
    }
    public event EventHandler CanExecuteChanged
    {
        add
        {
            CommandManager.RequerySuggested += value;
        }
        remove
        {
            CommandManager.RequerySuggested -= value;
        }
    }
    public void Execute(object parameter)
    {
        execute(parameter);
    }
}

and ofc i didnt test the code and i hope this is your looking for