Question

I have created a wpf application ,there are two canvas i would like to store controls of both cancas to one collection so that i can process them without two loop. What is the best method to implement this .

Answer 1

You could use LINQ’s Union operator to pull the two Canvas.Children collections together into one:

for (UIElement child in canvasOne.Children.Cast<UIElement>()
                                     .Union
                       (canvasTwo.Children.Cast<UIElement>()))
{
    ...
}

Note the following:

• The code shown doesn’t actually create a new, mutable collection that you can modify; it merely sets up an IEnumerable<UIElement> such that you can iterate over both collections’ elements in one go. That is, the two existing collections will be accessed, not a new one.

• The Cast<UIElement> operator is necessary because Canvas.Children does not implement IEnumerable<T>, but only IEnumerable.

• You need to reference the System.Core.dll assembly in your project, and import the System.Linq namespace in your code file for this to work.