wpf - bind autogeneratedcolumns datagrid to property of value

Question

My DataTable contains values of composite types for each column, the goal is for use both to dispaly the Value Property and style it by State Property

public class PairData
{
    public string Value { get; set; }
    public int State { get; set; }
}

it is possible to config the datagrid menualy like:

        <DataGrid.Columns>
            <DataGridTextColumn Binding="{Binding Path=Column1.Value}">
                <DataGridTextColumn.ElementStyle>
                    <Style TargetType="{x:Type TextBlock}">
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding Path=Column1.State}" Value="1">
                                <Setter Property="Background" Value="Red"/>
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </DataGridTextColumn.ElementStyle>
            </DataGridTextColumn>
        </DataGrid.Columns>

but i want to generate columns dinmicly using AutoGenerateColumns="True"

Is there a way to bind all columns for 'Value' Property? Perhaps something like:

      <DataGrid  ItemsSource="{Binding Path=Source}" >
        <DataGrid.CellStyle>
            <Style TargetType="DataGridCell">
                <Setter Property="Foreground" Value="Black" />
                <Setter Property="TextBlock.Text" Value="{Binding Value}"/>
            </Style>
        </DataGrid.CellStyle>
    </DataGrid>

I got an error:

System.Windows.Data Error: 40 : BindingExpression path error: 'Value' property not found on 'object' ''DataRowView' (HashCode=15375790)'. BindingExpression:Path=Value; DataItem='DataRowView' (HashCode=15375790); target element is 'DataGridCell' (Name=''); target property is 'Text' (type 'String')

can you please upload more detail code? – Byoung Sam Moon Dec 15 '19 at 23:48 — Byoung Sam Moon, Dec 15 '19 at 23:48

score 0 · Answer 1 · answered Dec 16 '19 at 13:55

0

You should replace the DataTable with an IEnumerable<PairData> implementation (like for example a List<PairData>).

You can't really store a custom object like PairData in a DataRow of a DataTable:

Binding an object to data grid cell - conditional cell style

answered Dec 16 '19 at 13:55

mm8

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`PairData` is not instead of `DataRow` ,is instead of cell value, all Column Type of `DataTable` are from `PairData` – mordechai Dec 17 '19 at 08:03
@mordechai: Didn't you read my answer? You cannot store custom objects in a `DataTable` so you shouldn't use one. – mm8 Dec 18 '19 at 10:06
why not, i do it, i have converted my `DataTable` to new` DataTable` with other columns type – mordechai Dec 19 '19 at 00:24
Maybe you should show *how* you have done this because you cannot solve your issue using a `DataTable` with custom objects in it. – mm8 Dec 19 '19 at 14:33
i can't do it here , because the question is closed, and the answer is too long... – mordechai Dec 21 '19 at 21:45
@mordechai: Edit the question. – mm8 Dec 30 '19 at 12:20

score 0 · Answer 2 · answered Jan 16 '20 at 09:31

this is the solution:

public abstract class StateExtension
{
    public abstract void SetValues(object value, Brush state);
}
public class StateExtension<T> : StateExtension
{

    public override void SetValues(object value, Brush state)
    {
        if (!(value is System.DBNull))
            Value = (T)value;
        State = state;
    }
    public T Value { get; set; }
    public Brush State { get; set; }
}

public static class DataTableEx
{
    public static DataTable ToDataTableEX(this DataTable dataTable)
    {

        var tb = new DataTable();
        Dictionary<int, Type> types = new Dictionary<int, Type>();
        var columnsCount = dataTable.Columns.Count;
        foreach (DataColumn column in dataTable.Columns)
        {
            var type = typeof(StateExtension<>).MakeGenericType(column.DataType);
            tb.Columns.Add(column.ColumnName, type);
            types.Add(column.Ordinal, type);
        }
        Type currentType = null;int x = 0;
        foreach (DataRow item in dataTable.Rows)
        {

            var values = new object[columnsCount];
            for (var i = 0; i < columnsCount; i++)
            {
                currentType = types[i];
                StateExtension instance = Activator.CreateInstance(currentType) as StateExtension;
                Brush state = GetStateBrush(item,x++);

                instance.SetValues(item[i], state);
                values[i] = instance;
            }

            tb.Rows.Add(values);
        }

        return tb;
    }

    private static Brush GetStateBrush(DataRow item,int i)
    {
        switch (i%3)
        {
            case 2:
                return LightGreen;
            case 1:
                return LightBlue;
            case 0:
            default:
                return LightGreen;
        }
    }
    static Brush LightPink = (Brush)new BrushConverter().ConvertFrom("LightPink");
    static Brush LightGreen = (Brush)new BrushConverter().ConvertFrom("LightGreen");
    static Brush LightBlue = (Brush)new BrushConverter().ConvertFrom("LightBlue");

}
public class DataGridBehavior : Behavior<DataGrid>
{



    protected override void OnAttached()
    {
         this.AssociatedObject.AutoGeneratingColumn += AssociatedObject_AutoGeneratingColumn;
    }


    private void AssociatedObject_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
    {
        try
        {
             if (e.PropertyType.IsSubclassOf(typeof(StateExtension)))
            {
                var binding = ((Binding)((DataGridTextColumn)e.Column).Binding);
                 binding.Path.Path = e.PropertyName + ".Value";
                Style cellStyle = new Style(typeof(DataGridCell));
                Setter backgroundSetter = new Setter(DataGridCell.BackgroundProperty, new Binding(e.PropertyName + ".State"));
                cellStyle.Setters.Add(backgroundSetter);
                ((DataGridTextColumn)e.Column).CellStyle = cellStyle;
            }
        }
        catch (Exception ex)
        {
             return;
        }
    }
 }

and xaml section is :

<DataGrid >
    <i:Interaction.Behaviors>
        <uiModel:DataGridBehavior  />
    </i:Interaction.Behaviors>
</DataGrid>

when i: is

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

wpf - bind autogeneratedcolumns datagrid to property of value

2 Answers2