Specify the max number of columns for a WrapPanel in WPF

Question

I have a WrapPanel, And I want to specify the Max number of its columns. So, for example, when my Collection \"ObjectCollection\" (binded to this WrapPanel) contains only 4 elem

Answer 1

Basically you're going to need to create a custom Panel for yourself... now don't get despondent... it's not that difficult. To start with, please take a look at the posts that I have provided links for that explain how to create a custom Panel:

How to create a Custom Layout Panel in WPF

Creating Custom Panels In WPF

Ok, so now that you know a bit more about creating custom Panels, we can continue... here's what you're going to need:

private int columnCount;
private double leftColumnEdge, rightColumnEdge, columnWidth;

public int ColumnCount
{
    get { return columnCount; }
    set
    {
        if (value < 1) value = 1;
        columnCount = value;
    }
}

This property would be used where you declare your Panel in Resources:

Note that you will need to declare it inside an ItemsPanelTemplate object because that is what the ItemsPanel property expects:

Now back to the Panel... here is a helper method that I call from the MeasureOverride and ArrangeOverride methods:

private void UpdateColumns(int currentColumn, Size finalSize)
{
    leftColumnEdge = (finalSize.Width / ColumnCount) * currentColumn;
    rightColumnEdge = (finalSize.Width / ColumnCount) * (currentColumn + 1);
    columnWidth = rightColumnEdge - leftColumnEdge;
}

Unfortunately for you, I cannot provide you with a complete example because my custom Panels are all tied into a base AnimatedPanel class with lots of additional functionality. However, you only need to create the MeasureOverride and ArrangeOverride methods to complete this Panel. If you just think logically about it, it's really not that difficult.