Setting a DataGrid background color based on the previous row
- by Zipper
I'm trying to setup a grid where I do column sorting, but I wanted to do zebra striping, only rather than every other row or every x rows, I want it to be based on the value of cells. i.e. All cells that contain 0 have a blue background, the next value would have a white background, the next value would be blue, etc....
The problem I have is that I can't seem to find where to actually do the setting of the background colors. I'm using a custom sorter and I tried setting it in there after I re-order the list and set the data source, but it appears that when the data source is set, that the rows don't exist yet. I tried using the DataContextChanged, but that event doesn't seem to be firing.
Here is what I have now.
namespace Foo.Bar
{
public partial class FooBar
{
List<Bla> ResultList { get; set; }
SolidColorBrush stripeOneColor = new SolidColorBrush(Colors.Gold);
SolidColorBrush stripeTwoColor = new SolidColorBrush(Colors.White);
//*********************************************************************************************
public Consistency()
{
InitializeComponent();
}
//*********************************************************************************************
override protected void PopulateTabWithData()
{
ResultList = GetBlas();
SortAndGroup("Source");
}
//*********************************************************************************************
private void SortAndGroup(string colName)
{
IOrderedEnumerable <Bla> ordered = null;
switch (colName)
{
case "Source":
case "ID":
ordered = ResultList.OrderBy(r => r.Source).ThenBy(r => r.ID);
break;
case "Name":
ordered = ResultList.OrderBy(r => r.Source).ThenBy(r => r.Name);
break;
case "Message":
ordered = ResultList.OrderBy(r => r.Message);
break;
default:
throw new Exception(colName);
}
ResultList = ordered.ThenBy(r => r.Source).ThenBy(r => r.ID).ToList(); // tie-breakers
consistencyDataGrid.ItemsSource = null;
consistencyDataGrid.ItemsSource = ResultList;
ColorRows();
}
//*********************************************************************************************
private void consistencyDataGrid_Sorting(object sender, System.Windows.Controls.DataGridSortingEventArgs e)
{
SortAndGroup(e.Column.Header.ToString());
e.Handled = true;
}
private void ColorRows()
{
for (var i = 0; i < ResultList.Count; i++)
{
var currentItem = ResultList[i];
var row = myDataGrid.ItemContainerGenerator.ContainerFromItem(currentItem) as DataGridRow;
if (row == null)
{
continue;
}
if (i > 0)
{
var previousItem = ResultList[i - 1];
var previousRow = myDataGrid.ItemContainerGenerator.ContainerFromItem(previousItem) as DataGridRow;
if (currentItem.Source == previousItem.Source)
{
row.Background = previousRow.Background;
}
else
{
if (previousRow.Background == stripeOneColor)
{
row.Background = stripeTwoColor;
}
else
{
row.Background = stripeOneColor;
}
}
}
else
{
row.Background = stripeOneColor;
}
}
}
}
}
}
