I am not able to set DataContext from code behind of one userControl to another userControl

Question

I am not able to set DataContext from code behind of one userControl to another userControl .

private void grdWorkingList_MouseDoubleClick(object sender, System.Windows.Input.MouseButtonEventArgs e) {
    DashboardSynopsisViewModel dsViewModel = new DashboardSynopsisViewModel();
    AuditInfoViewModel auditInfoViewModel = new AuditInfoViewModel();

    AuditInfoView auditInfoView = new AuditInfoView();
    var selectedItem = (grdWorkingList.SelectedItem as AutoMgmtSoln.AuditWinPro.ClientData.Model.AuditDTO); 

    // MainWindow mainWindow = new MainWindow();
    DSViewContentControl.Content = new AuditInfoView();

    auditInfoView.DataContext = auditInfoViewModel;
    auditInfoViewModel.AuditDTO = auditInfoViewModel.getAuditById(selectedItem.AuditId); 
}

I have two user controls DashboardSynopsisView and AuditInfoView having view models DashboardSynopsisViewModel and AuditInfoViewModel. So in the code behind I have a event grdWorkingList_MouseDoubleClick which is fired on mouseDouble click which sets the content control of the dashboardSynopsisView to the AuditInfoView along with it's DataContext to AuditInfoViewModel. AuditInfoViewModel has a property AuditDTO which I am using to display information of the selected item.

Here is part of my .xaml file

<TextBlock Grid.Column="0" Grid.Row="0"  Text="Company Code :"></TextBlock>
<TextBlock Grid.Column="1" Grid.Row="0" Width="auto" Text="{Binding  AuditDTO.CompanyCode}" ></TextBlock>

<TextBlock Grid.Column="0" Grid.Row="1" >Company Name :</TextBlock>
<TextBlock Grid.Column="1" Grid.Row="1" Width="auto" Text="{Binding  AuditDTO.CompanyName}" ></TextBlock>

Here is the change I have made to resolve my the problem .

 private void grdWorkingList_MouseDoubleClick(object sender, System.Windows.Input.MouseButtonEventArgs e)
    {

        DashboardSynopsisViewModel dsViewModel = new DashboardSynopsisViewModel();
        AuditInfoViewModel auditInfoViewModel = new AuditInfoViewModel();

        AuditInfoView auditInfoView = new AuditInfoView();
        var selectedItem = (grdWorkingList.SelectedItem as AutoMgmtSoln.AuditWinPro.ClientData.Model.AuditDTO); 


       // MainWindow mainWindow = new MainWindow();
        DSViewContentControl.Content = ***auditInfoView***;

        auditInfoView.DataContext = auditInfoViewModel;
        auditInfoViewModel.AuditDTO = auditInfoViewModel.getAuditById(selectedItem.AuditId); 

    }

Answer 1

You are setting the "auditInfoView" variable's data context, but setting the content control to a new AuditInfo view.

Make these match (probably by changing the content set to the auditInfoView variable) and your code should work.

To provide a little background, in case you are new to C#, using the new operator causes the class's constructor to be invoked, which creates a new object with default values (plus any sets or operations done by the constructor itself). Setting another instance's DataContext property will have no effect on the newly constructed instance.