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I am having an grid holding in Button. I want to set corner radius for this button by programmatically in xamarin.uwp. If it possible means i want to set corner radius for Bottom left alone. Please suggest your ideas for this query.

For your requirement, you could custom BottomLeft BindableProperty. then use it in your custom button render like the following.

Custom Forms buttom

public class MyButton : Button


 public static readonly BindableProperty BottomLeftProperty = BindableProperty.Create(
 propertyName: "BottomLeft",
 returnType: typeof(int),
 declaringType: typeof(MyButton),
 defaultValue: default(int));

 public int BottomLeft
 
 get return (int)GetValue(BottomLeftProperty); 
 set SetValue(BottomLeftProperty, value); 
 

CustomButtonRenderer.cs

public class CustomButtonRenderer : ButtonRenderer

 Windows.UI.Xaml.Controls.ContentPresenter _contentPresenter;
 MyButton _myElement;
 protected override void OnElementChanged(ElementChangedEventArgs<Button> e)
 
 base.OnElementChanged(e);
 if (Control == null)
 
 SetNativeControl(new FormsButton());
 
 if (e.NewElement != null)
 
 Control.Loaded += Control_Loaded;
 _myElement = Element as MyButton;
 
 

 protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
 
 base.OnElementPropertyChanged(sender, e);

 if (e.PropertyName == MyButton.BottomLeftProperty.PropertyName)
 
 UpdateBottomLeftBorderRadius(_myElement.BottomLeft);
 
 

 private void Control_Loaded(object sender, Windows.UI.Xaml.RoutedEventArgs e)
 
 _contentPresenter = MyFindChildByName(Control, "ContentPresenter") as Windows.UI.Xaml.Controls.ContentPresenter;

 if (_myElement.IsSet(MyButton.BottomLeftProperty) && _myElement.BottomLeft != (int)MyButton.BottomLeftProperty.DefaultValue)
 
 UpdateBottomLeftBorderRadius(_myElement.BottomLeft);
 
 

 private void UpdateBottomLeftBorderRadius(int bottomLeft)
 
 if (_contentPresenter != null)
 
 _contentPresenter.CornerRadius = new CornerRadius(0, 0, 0, bottomLeft);
 

 

 public static DependencyObject MyFindChildByName(DependencyObject parant, string ControlName)
 
 int count = VisualTreeHelper.GetChildrenCount(parant);

 for (int i = 0; i < count; i++)
 
 var MyChild = VisualTreeHelper.GetChild(parant, i);
 if (MyChild is FrameworkElement && ((FrameworkElement)MyChild).Name == ControlName)
 return MyChild;

 var FindResult = MyFindChildByName(MyChild, ControlName);
 if (FindResult != null)
 return FindResult;
 
 return null;
 

Usage

<local:MyButton x:Name="Hello" Text="hello" 
 WidthRequest="100" 
 HeightRequest="100" 
 Margin="0,100,0,0" 
 BottomLeft="15" 
 VerticalOptions="Center" 
 HorizontalOptions="Center" 
 Clicked="MyButton_Clicked"/>

For edit the bottom left property programatically.

HelloBtn.BottomLeft = 30;