Silverlight is a powerful tool used for developing rich internet applications. One of its key features is the ability to create and customize data grids, making it a popular choice among developers. The Silverlight data grid is a powerful control that allows users to display and manipulate data in a tabular format. In this article, we will explore how to enhance the Silverlight data grid by conditionally changing cell styles.
Before we dive into the details, let's first understand what is meant by "conditionally changing cell styles". In simple terms, it means that the appearance of a cell in the data grid will change based on certain conditions. For example, you may want to highlight a cell with a different color if it meets a specific criteria or display a different font style for cells that contain negative values.
To achieve this, we will make use of the Style and DataTrigger elements in Silverlight. A Style is a set of formatting properties that can be applied to a control, while a DataTrigger allows us to set a specific condition for the Style to be applied. Let's see how this works in practice.
First, we need to define a Style for the cells in our data grid. This can be done in the Resources section of the XAML code. We will name our Style as "ConditionalCellStyle" and specify the formatting properties we want to apply, such as FontSize, FontWeight, and Foreground color.
<Grid.Resources>
<Style x:Key="ConditionalCellStyle" TargetType="sdk:DataGridCell">
<Setter Property="FontSize" Value="14"/>
<Setter Property="FontWeight" Value="Bold"/>
<Setter Property="Foreground" Value="Black"/>
</Style>
</Grid.Resources>
Next, we will create a DataTrigger within this Style. This DataTrigger will check for a specific condition, and if it is met, it will change the cell's background color to red.
<DataTrigger Binding="{Binding Value}" Value="Negative">
<Setter Property="Background" Value="Red"/>
</DataTrigger>
In the above code, we have specified the binding to be the "Value" property of the cell, and the condition is set to "Negative". This means that whenever the cell's value is negative, the background color will change to red.
Now, we need to apply this Style to our data grid cells. This can be done by setting the CellStyle property of the data grid to our "ConditionalCellStyle".
<sdk:DataGrid CellStyle="{StaticResource ConditionalCellStyle}">
And that's it! Our data grid cells will now have a bold font, font size of 14, and a red background color if the value is negative. You can customize this to your liking by changing the formatting properties and the conditions inside the DataTrigger.
But what if we want to change the cell style based on a different condition? For example, we may want to change the font color to green if the value is positive. In that case, we can add another DataTrigger for the same Style.
<DataTrigger Binding="{Binding Value}" Value="Positive">
<Setter Property="Foreground" Value="Green"/>
</DataTrigger>
Now, both conditions will be checked, and the cell style will change accordingly. This is the beauty of using DataTriggers - we can have multiple conditions and different styles for each one.
In addition to changing the cell style, we can also use DataTriggers to change other properties, such as
