I have a GridView where for certain the values are Nullable Booleans, when the value happens to be null, the controls renders a CheckBox with the IsTrueState property to true, presenting a CheckBox with a minus sign on it, something I feel is quite unnoticeable, so I decided to color the cell with a background color but only when the condition of being null is met. the problem is that the binding seems to be ignored by the control
I have the following code: For the Value Converter.
I have the following code: For the Value Converter.
public class TriStateBooleanToStyleValueConverter : IValueConverter
{
public object Convert(object value,
Type targetType,
object parameter,
System.Globalization.CultureInfo culture)
{
ResourceDictionary converterDictionary = new ResourceDictionary()
{
Source = new Uri("/SilverlightApplication1;component/Assets/Styles.xaml", UriKind.RelativeOrAbsolute)
};
if (value == null)
{
return converterDictionary["NullCellRedStyle"] as Style;
}
else
{
return converterDictionary["NullCellWhiteStyle"] as Style;
}
}
public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
{
throw new NotImplementedException();
}
}
For the Styles defined in Styles.xaml<Style x:Key="NullCellRedStyle" TargetType="telerik:GridViewCell">Also have the Converter defined as a resource in the same styles file
<Setter Property="Background" Value="#FFFFD8D8"/>
</Style>
<Style x:Key="NullCellWhiteStyle" TargetType="telerik:GridViewCell">
<Setter Property="Background" Value="#FFFFFFFF"/>
</Style>
<converters:TriStateBooleanToStyleValueConverter x:Key="TriBoolToStyle"/>At the column level I have the following:
<telerik:GridViewDataColumn Header="To Pay" MinWidth="70" Width="90" DataMemberBinding="{Binding Path=ToPay}" CellStyle="{Binding Path=ToPay, Converter={StaticResource TriBoolToStyle}}" />I define the CellStyle directly without binding and it works, also, I placed a breakpoint into the converter and it is never reached.
Thanks
Juan Mejia
3 Answers, 1 is accepted
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Accepted
Hello,
Vlad
the Telerik team
You cannot use Binding in this case since the context of the column is the context of the grid it self - not the data item. You can put desired control in CellTemplate and apply the same binding - in this case everything will work as expected. It will be better however if you use our CellStyleSelector instead - it will be easier.
Kind regards,Vlad
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Juan
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answered on 03 Sep 2010, 04:09 PM
Your tip showed me the way to implement it, I am sharing my solutions for others to use in case they face the same issue.
I created a ConditionalNullStyleSelector class this way:
In the Styles file
And In the GridView
Juan Mejia
I created a ConditionalNullStyleSelector class this way:
public class ConditionalNullStyleSelector : StyleSelector { public enum CellColumn { HasDiscount, Price, InStock } public override Style SelectStyle(object item, DependencyObject container) { Product product; Style style = null; if(item is Product) { product = (Product)item; switch(ColumnToCheck) { case CellColumn.HasDiscount: style = PickStyle(product.HasDiscount); break; case CellColumn.Price: style = PickStyle(product.Cost); break; case CellColumn.InStock: style = PickStyle(product.InStock); break; default: style = PickStyle(0); break; } } return style; } public CellColumn ColumnToCheck { get; set; } private Style PickStyle(object value) { ResourceDictionary converterDictionary = new ResourceDictionary() { Source = new Uri("/SilverlightApplication1;component/Assets/Styles.xaml",
UriKind.RelativeOrAbsolute) }; if (value == null) { return converterDictionary["NullCellRedStyle"] as Style; } else { return converterDictionary["NullCellWhiteStyle"] as Style; } } }In the Styles file
<helpers:ConditionalNullStyleSelector x:Key="HasDiscountStyleSelector" ColumnToCheck ="HasDiscount"/> <helpers:ConditionalNullStyleSelector x:Key="PriceStyleSelector" ColumnToCheck ="Price"/> <helpers:ConditionalNullStyleSelector x:Key="InStockStyleSelector" ColumnToCheck ="InStock"/> <Style x:Key="NullCellRedStyle" TargetType="telerik:GridViewCell"> <Setter Property="Background" Value="#FFFFD8D8"/> </Style> <Style x:Key="NullCellWhiteStyle" TargetType="telerik:GridViewCell"> <Setter Property="Background" Value="#FFFFFFFF"/> </Style>And In the GridView
<telerik:GridViewDataColumn Header="Has Discount" DataMemberBinding="{Binding Path=HasDiscount}" CellStyleSelector="{StaticResource HasDiscountStyleSelector}" /> <telerik:GridViewDataColumn Header="Price" DataMemberBinding="{Binding Path=Price}" DataFormatString="{} {0:C0}" CellStyleSelector="{StaticResource PriceStyleSelector}" /> <telerik:GridViewDataColumn Header="InStock" DataMemberBinding="{Binding Path=InStock}" CellStyleSelector="{StaticResource InStockStyleSelector}" />Juan Mejia
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Ben
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answered on 14 Feb 2012, 04:50 PM
privatevoid grdWorkOrderItems_RowLoaded(object sender, RowLoadedEventArgs e) { if (e.Row is GridViewRow) { foreach (GridViewCell cell in e.Row.Cells) { switch (cell.Column.UniqueName) { case "selectColumn": break; case "omrsColumn": break; default: Binding cellStyleBinding = new Binding { Source = e.Row.DataContext, Path = new PropertyPath("IsChecked"), Converter = LayoutRoot.Resources["CheckedStyleSelector"] as IValueConverter, }; cell.SetBinding(GridViewCell.StyleProperty, cellStyleBinding); break; } } } }For the sake of completeness, I was actually able to bind to the cell style and supply a converter as in the first example by setting the Binding source in the codebehind such as in the above code...I didn't; however, test it long enough to determine if there were any major issues, as that technique proved to be pointless after I got the CellStyleSelector working correctly...regards,
Ben