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CellLoaded event question

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GridView

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Jeff asked on 23 Nov 2010, 06:59 PM

In an in-browser application, I'm trying to change the foreground color of cells whose text starts with a "!" in the code-behind as shown here:

radGridView1.CellLoaded += (s, f) =>

{

if (f.Cell.GetType() != typeof(GridViewCell)) return;

GridViewCell cur = (GridViewCell)f.Cell;

if (cur.Value == null) return;

if (cur.Value.ToString().Length == 0) return;

if (cur.Value.ToString()[0] == '!')

{

cur.Foreground = new SolidColorBrush(Colors.Gray);

}

};

I adapted the datatable object described here (located in the data.cs file) as the grid's itemssource.

For some reason, random cells are have their color changed as I scroll up and down through the table (the data stays correct, however). Sometimes they are cells that contain exclamation marks, other times they are not. Cells that were black when I passed by them scrolling down are suddenly gray as I scroll past them going up and vice versa.

I'm using the current version of the library (downloaded last week). Any ideas?

Jeff

8 Answers, 1 is accepted

answered on 24 Nov 2010, 10:31 PM

Thanks for the updated link and my apologies for not spending more time looking through the Telerik blogs first.

As for the styling, I'm trying to do this in the code-behind because I only want to apply the colors to particular cells (not the first row nor the first or second columns, for example). I couldn't find anything in the documentation showing how best to apply styles to specific cells in the code-behind. However, when I tried what you described in your Feb 3, 2009 blog entry, it had the same problem as before - applying the gray foreground to random cells which change as I scroll up and down through the grid. I made a sample project including your datatable and a default datagrid in the XAML that demonstrates the problem I'm having:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using Telerik.Windows.Controls.GridView;

using Telerik.Data;

using Telerik.Windows;

using Telerik.Windows.Data;

using Telerik.Windows.Controls;

namespace GrayGrid

{

public partial class MainPage : UserControl

{

public MainPage()

{

Loaded += new RoutedEventHandler(MainPage_Loaded);

InitializeComponent();

}

private void MainPage_Loaded(object sender, RoutedEventArgs e)

{

DataTable dt = new DataTable();

dt.Columns.Add(new DataColumn() { ColumnName = "C0", DataType = typeof(string) });

dt.Columns.Add(new DataColumn() { ColumnName = "C1", DataType = typeof(string) });

dt.Columns.Add(new DataColumn() { ColumnName = "C2", DataType = typeof(string) });

DataRow row = null;

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "!xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "!xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "!xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "!xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "!xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

row = dt.NewRow(); row["C0"] = "xx"; row["C1"] = "xx"; row["C2"] = "xx"; dt.Rows.Add(row);

radGridView1.Loaded += (s, f) =>

{

var cell = radGridView1.ChildrenOfType<GridViewCell>().Where(cur => cur.Value != null && cur.Value.ToString().Length > 0 && cur.Value.ToString()[0] == '!').ToList();

cell.ForEach(cur => cur.Foreground = new SolidColorBrush(Colors.Gray));

};

radGridView1.ItemsSource = dt;

}

Can you take a look and let me know what direction I should take on this? Thanks!

Jeff

answered on 27 Nov 2010, 03:22 AM

I was sort of able to do what you suggested by adapting the CellStyleSelector solution that Maya demonstrated here, but it appears to have the same problem. Below is my code, modified to use CellStyleSelector. Note that I edited the ConditionalStyleSelector class to pass the GridViewCell object to the converter function, which may be the source of the problem. It appeared that I had to do it this way because the item object sent to the CellStyleSelector is the entire row, not the cell being tested, so I had no idea which column to check vs. the exclamation point.

When I tell it to test a particular cell in the item, that is, pass the entire row item and tell it to check a particular one of them, it appears to work correctly, but this is impractical because there will be an arbitrary number of columns in the report and I can't provide a separate CellStyleSelector function for each of them.

Anyway, here's the code:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using Telerik.Windows.Controls.GridView;

using Telerik.Data;

using Telerik.Windows;

using Telerik.Windows.Data;

using Telerik.Windows.Controls;

using System.Windows.Data;