Is there any way to change the style of gridlines in wpf grid? I need to divide grid into 4 cells. To do it I used RowDefinitions and ColumnDefinitions. However I need user to distinguish which cell is which, that's why I need to change the color of the gridlines.
It depends on the look you are going for. In WPF, there are different ways to do almost anything. Here are a couple of the easier ones.
The easiest way is to set ShowGridlines="True":
<Grid HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Margin="5"
ShowGridLines="True">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<TextBlock Grid.Column="0"
Grid.Row="0"
Text="(0,0)" />
<TextBlock Grid.Column="1"
Grid.Row="0"
Text="(1,0)" />
<TextBlock Grid.Column="0"
Grid.Row="1"
Text="(0,1)" />
<TextBlock Grid.Column="1"
Grid.Row="1"
Text="(1,0)" />
</Grid>
That gives you grid something like:
You can also use a Rectangle in each cell of the grid to get different effects. Here, the Fill is transparent and the Stroke is Blue:
<Grid HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Margin="5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Rectangle Grid.Column="0"
Grid.Row="0"
Stroke="Blue"
Fill="Transparent" />
<TextBlock Grid.Column="0"
Grid.Row="0"
Text="(0,0)" />
<Rectangle Grid.Column="1"
Grid.Row="0"
Stroke="Blue"
Fill="Transparent" />
<TextBlock Grid.Column="1"
Grid.Row="0"
Text="(1,0)" />
<Rectangle Grid.Column="0"
Grid.Row="1"
Stroke="Blue"
Fill="Transparent" />
<TextBlock Grid.Column="0"
Grid.Row="1"
Text="(0,1)" />
<Rectangle Grid.Column="1"
Grid.Row="1"
Stroke="Blue"
Fill="Transparent" />
<TextBlock Grid.Column="1"
Grid.Row="1"
Text="(1,0)" />
</Grid>
That produces this:
Alternatively, you can fill the Rectangles and not give them a Stroke:
<Grid HorizontalAlignment="Stretch"
VerticalAlignment="Stretch"
Margin="5">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Rectangle Grid.Column="0"
Grid.Row="0"
Fill="LightBlue" />
<TextBlock Grid.Column="0"
Grid.Row="0"
Text="(0,0)" />
<Rectangle Grid.Column="1"
Grid.Row="0"
Fill="LightYellow" />
<TextBlock Grid.Column="1"
Grid.Row="0"
Text="(1,0)" />
<Rectangle Grid.Column="0"
Grid.Row="1"
Fill="LightYellow" />
<TextBlock Grid.Column="0"
Grid.Row="1"
Text="(0,1)" />
<Rectangle Grid.Column="1"
Grid.Row="1"
Fill="LightBlue" />
<TextBlock Grid.Column="1"
Grid.Row="1"
Text="(1,0)" />
</Grid>
That can, for instance, give a checkerboard pattern:
This is by no means a comprehensive answer - you could probably fill a book. It was just meant to show that there are many ways to do what you are asking, and that there are some pretty quick and easy solutions if that's all you need.