从单独的cs/命名空间更改多个页面中的xaml控件的值

<Label x:Name="myLabel" Text="Old Text" />

myLabel.Text = "New Text";

public class MyHelper
{
    public static void UpdateLabelText(Label label, string newText)
    {
        label.Text = newText;
    }
}

MyHelper.UpdateLabelText(myLabel, "New Text");