Example provided fails on... System.Data.DataRowView drv = (System.Data.DataRowView)value;

Example provided fails on... System.Data.DataRowView drv = (System.Data.DataRowView)value;
System.NotImplementedException: 'Unable to cast object of type

---

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: a0e7271e-65e1-6484-aa46-37b3e44828d0
• Version Independent ID: 07f27f2e-e1a9-e536-1c5d-b9c3c9798a0a
• Content: DataGrid.RowHeaderStyle Property (System.Windows.Controls)
• Content Source: xml/System.Windows.Controls/DataGrid.xml
• Product: dotnet-api
• GitHub Login: @dotnet-bot
• Microsoft Alias: dotnetcontent

[MSDN-WhiteKnight]

The example assumes that DataGrid is bound to DataView, but it is not stated anywhere. If we bind DataGrid like this:

public MainWindow()
{
        InitializeComponent();
        DataTable dt = new DataTable();
        //...
        this.DataContext = dt.DefaultView;
}

everything works properly. If we bind DataGrid to any other collection, the error is reproduced.

I think, there's no need to cast source item into DataRowView for purposes of this example, so it can be fixed by rewriting Convert method like this:

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
    try
    {                
        //Get the CollectionView from the DataGrid that is using the converter
        DataGrid dg = (DataGrid)Application.Current.MainWindow.FindName("DG1");
        CollectionView cv = (CollectionView)dg.Items;
        //Get the index of the item from the CollectionView
        int rowindex = cv.IndexOf(value) + 1;

        return rowindex.ToString();
    }
    catch (Exception e)
    {
        throw new NotImplementedException(e.Message);
    }
}

It should work with any collection.

Thanks for the response. It is somewhat confusing whilst learning C# when Microsoft examples fail. I don’t know if this occurs because C# is evolving or the examples provided are not tested (as in downloaded in isolation from original composition) or lack the documented conditions required. But given the scale of C# possibilities, and the effort required to document every possibility! I have little to complain about. Again, thankyou for your response. Cheers, Ray

…

________________________________ From: MSDN.WhiteKnight <notifications@github.com> Sent: Wednesday, April 24, 2019 1:36:37 PM To: dotnet/dotnet-api-docs Cc: Ray-Wynn; Author Subject: Re: [dotnet/dotnet-api-docs] Example provided fails on... System.Data.DataRowView drv = (System.Data.DataRowView)value; (#1911) The example assumes that DataGrid is bound to DataView, but it is not stated anywhere. If we bind DataGrid like this: public MainWindow() { InitializeComponent(); DataTable dt = new DataTable(); //... this.DataContext = dt.DefaultView; } everything works properly. If we bind DataGrid to any other collection, the error is reproduced. I think, there's no need to cast source item into DataRowView for purposes of this example, so it can be fixed by rewriting Convert method like this: public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture) { try { //Get the CollectionView from the DataGrid that is using the converter DataGrid dg = (DataGrid)Application.Current.MainWindow.FindName("DG1"); CollectionView cv = (CollectionView)dg.Items; //Get the index of the item from the CollectionView int rowindex = cv.IndexOf(value) + 1; return rowindex.ToString(); } catch (Exception e) { throw new NotImplementedException(e.Message); } } It should work with any collection. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fdotnet%2Fdotnet-api-docs%2Fissues%2F1911%23issuecomment-486054532&data=02%7C01%7C%7Ca1d4da44327c4c87d06e08d6c8660feb%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636916738004157111&sdata=Oo20wBQLdLbf%2BHJ9CdWHFYCd30CxFUjdokf8mNUgJSo%3D&reserved=0>, or mute the thread<https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fnotifications%2Funsubscribe-auth%2FAHIHM2DRQ5EQ7GGEEZ6F5TDPR7IULANCNFSM4GYZOPRA&data=02%7C01%7C%7Ca1d4da44327c4c87d06e08d6c8660feb%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636916738004157111&sdata=YMia4rzynSCUdOT%2BV01xb5WQ0n94KAhCKMZucBpTiK0%3D&reserved=0>.