Search code examples
wpfdatatablecastingdatagrid

WPF How to convert from DataGrid to DataTable?

Hi I am following along with this guide in order to learn about using DataGrid.

The problem I am running into is how do I convert the data from the DataGrid into a DataTable?

The code I am trying to get working is:

DataTable dt = ((DataView)dg.ItemsSource).ToTable();

but it gives me an error stating:

Unable to cast object of type 'System.Collections.Generic.List`1[WPFProject.Person]' to type 'System.Data.DataView'.

My code is very much similar to the example except I use the class Person instead of user and I create a list of type Person in order to insert data into the datagrid.

public class Person
    {
        public bool CheckBox { get; set; }
        public int ID { get; set; }
        public string Name { get; set; }
    }

Thank you.

Solution

  • You can't convert it that way. Your code will only work if the ItemSource of your DataGrid is not a DataView. You need to write code explicitly (which you can easily google any collection<T> to DataTable) to convert your collection into DataTable. have a look at below example:

    XAML

      <StackPanel>
    <DataGrid ItemsSource="{Binding list}" x:Name="myGrid"/>
    <Button Content="convert back" Click="Button_Click_1" />
</StackPanel>

    Logic:

    private void Button_Click_1(object sender, RoutedEventArgs e)
    {
        var list = new List<MyClass>(myGrid.ItemsSource as IEnumerable<MyClass>);
        var dataTable = ToDataTable(list);
        if (dataTable != null)
        {

        }
    }

    public static DataTable ToDataTable<T>(List<T> items)
    {
        DataTable dataTable = new DataTable(typeof(T).Name);

        //Get all the properties
        PropertyInfo[] Props = typeof(T).GetProperties(BindingFlags.Public | BindingFlags.Instance);
        foreach (PropertyInfo prop in Props)
        {
            //Setting column names as Property names
            dataTable.Columns.Add(prop.Name);
        }
        foreach (T item in items)
        {
            var values = new object[Props.Length];
            for (int i = 0; i < Props.Length; i++)
            {
                //inserting property values to datatable rows
                values[i] = Props[i].GetValue(item, null);
            }
            dataTable.Rows.Add(values);
        }
        //put a breakpoint here and check datatable
        return dataTable;
    }

    Output

    Grid

    DataTable