Accessing XAML elements from C# using string or arrays

Question

I am new to WindowsApp Development and I was trying to access XAML elements through C# code using an array. For example I have few ellipses in my XAML code-

<Ellipse Fill="#FFF4F4F5" x:Name="E_0" Grid.Row="0" Grid.Column="2" Stroke="Black" RenderTransformOrigin="0.474,5.849"  Visibility="Visible" HorizontalAlignment="Center" VerticalAlignment="Center" />
<Ellipse Fill="#FFF4F4F5" x:Name="E_1" Grid.Row="0" Grid.Column="3" Stroke="Black" RenderTransformOrigin="0.474,5.849"  Visibility="Visible" HorizontalAlignment="Center" VerticalAlignment="Center"/>
<Ellipse Fill="#FFF4F4F5" x:Name="E_2" Grid.Row="0" Grid.Column="4" Stroke="Black" RenderTransformOrigin="0.474,5.849"  Visibility="Visible" HorizontalAlignment="Center" VerticalAlignment="Center"/>

Now I want to work with them in C# in a loop so I am doing something similar to the following-

string s1="E_";
double width=500;
for (int i = 0; i < 2;i++ )
 {
    string name_i = s1 + i.ToString();
    name_i.Width = width / 2;
 }

But name_i.width gives me an error. So, do I have to use the actual names, is there no way I can use an array or string? Using the actual names will defeat the purpose as I have about 50 such elements which I need to work upon.

And if you'd group the Ellipse objects in a container and give that container a variable name, couldn't you loop through the Children of that container and affect every eclipse thereby? — Maximilian Gerhardt
– Maximilian Gerhardt, Commented Feb 3, 2016 at 19:49
Maybe, I am not sure, actually I do have all the Ellipses in a Grid by the name of Game. But if I enumerate the children, how can I check only for the Ellipse elements and not other elements present in that Grid? — Noober
– Noober, Commented Feb 3, 2016 at 19:55
Will that not require two loops- an outer loop iterating over Children and the inner loop iterating over my var ellipses. Is there some way, I can do this using a single array instead of Container because if it is possible, the n I think it would be more efficient. — Noober
– Noober, Commented Feb 3, 2016 at 20:08
No, I meant you either group them in a container and iterate over the Children, or you group them in an array by code with the Ellipse[] ellipses = { ... }; and iterate over this array, but not both at once. — Maximilian Gerhardt
– Maximilian Gerhardt, Commented Feb 3, 2016 at 20:10
Since you've defined ` x:Name="E_0"` etc. in every eclipse you should have this variable name available, so that works and should compile. Eh, maybe with a new Ellipse[] before the { but I think that has become redundant with newer C# versions. — Maximilian Gerhardt
– Maximilian Gerhardt, Commented Feb 3, 2016 at 20:16

Philip W · Accepted Answer · 2016-02-03 20:01:04Z

2

As Maximillian proposed, you can use the parent container and iterate over its children:

Xaml:

 <StackPanel Name="StackPanelContainer">
      <Grid></Grid>
      <Ellipse Name="E_0"></Ellipse>
      <Ellipse Name="E_1"></Ellipse>
      <Ellipse Name="E_2"></Ellipse>
    </StackPanel>

Codebehind:

        //if you are sure every child element is a ellipse, you can use:
        foreach (Ellipse child in StackPanelContainer.Children)
        {
            child.Width = 100;
        }

        //if there are also other elements, and also check if name starts with "E_"
        foreach (object child in StackPanelContainer.Children)
        {
            var ellipse = child as Ellipse;
            if (ellipse != null && ellipse.Name.StartsWith("E_"))
            {
                ellipse.Width = 100;
            }
        }

answered Feb 3, 2016 at 20:01

Philip W

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1 Comment

Noober Over a year ago

Thanks but is there some other way to achieve this using arrays. This is because this will mostly not work if I want to work with just some of the Ellipses. Say I want to change Width of only some 15 out of 50 Ellipses, then comparing each of them with their name will involve two loops(if I am correct)-one outer loop iterating over the Children and the other loop which will iterate over my array where I will compare the names of the Children.

Alex Isayenko · Accepted Answer · 2016-02-03 22:04:07Z

2

Use FindName() method.

string s1 = "E_";
double width = 500;
for (int i = 0; i < 2; i++)
{
    string name_i = s1 + i.ToString();

    var ellipse = FindName(name_i) as Ellipse;

    if (ellipse != null)
    {
        ellipse.Width = width / 2;
    }
}

answered Feb 3, 2016 at 22:04

Alex Isayenko

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