How to handle events in RangeSlider of Xamarin.Forms platform?
In our latest 2017 Volume 2, we have removed Delegate API and SFRangeSliderDelegate class from SfRangeSlider control. Here we have explained how to hook the events using event handler instead of delegates.
The below codes explain how to hook the event using delegate class in our old implementation.
Code snippet:
namespace DelegateToEvent{ public partial class ViewController : UIViewController { protected ViewController(IntPtr handle) : base(handle) { // Note: this .ctor should not contain any initialization logic. } public override void ViewDidLoad() { base.ViewDidLoad(); SFRangeSlider slider = new SFRangeSlider(); slider.Frame = new CoreGraphics.CGRect(10, 50, this.View.Frame.Width-20,400); slider.Delegate =new RangeSliderDelegate(); this.View.AddSubview(slider); // Perform any additional setup after loading the view, typically from a nib. } public override void DidReceiveMemoryWarning() { base.DidReceiveMemoryWarning(); // Release any cached data, images, etc that aren't in use. } } public class RangeSliderDelegate : SFRangeSliderDelegate { public override void ValueChange(SFRangeSlider SFRangeSlider, nfloat value) { nfloat Value = value; } public override void RangeValueChange(SFRangeSlider SFRangeSlider, nfloat start, nfloat end) { nfloat RangeStart = start; nfloat RangeEnd = end; } }}
Step 1:Include the ValueChange and RangeChange Event handler as follows.
namespace DelegateToEvent{ public partial class ViewController : UIViewController { protected ViewController(IntPtr handle) : base(handle) { // Note: this .ctor should not contain any initialization logic. } public override void ViewDidLoad() { base.ViewDidLoad(); SFRangeSlider slider = new SFRangeSlider(); slider.Frame = new CoreGraphics.CGRect(10, 50, this.View.Frame.Width - 20, 400); //RangeSlider ValueChange event slider.ValueChange += (sender, e) => { }; //RangeSlider RangeChagne event slider.RangeValueChange += (sender, e) => { }; slider.Delegate =new RangeSliderDelegate(); this.View.AddSubview(slider); // Perform any additional setup after loading the view, typically from a nib. } public override void DidReceiveMemoryWarning() { base.DidReceiveMemoryWarning(); // Release any cached data, images, etc that aren't in use. } } public class RangeSliderDelegate : SFRangeSliderDelegate { public override void ValueChange(SFRangeSlider SFRangeSlider, nfloat value) { nfloat Value = value; } public override void RangeValueChange(SFRangeSlider SFRangeSlider, nfloat start, nfloat end) { nfloat RangeStart = start; nfloat RangeEnd = end; } }}
Step 2: Include the your business logic to new events which you have written in delegate class.
namespace DelegateToEvent{ public partial class ViewController : UIViewController { protected ViewController(IntPtr handle) : base(handle) { // Note: this .ctor should not contain any initialization logic. } public override void ViewDidLoad() { base.ViewDidLoad(); SFRangeSlider slider = new SFRangeSlider(); slider.Frame = new CoreGraphics.CGRect(10, 50, this.View.Frame.Width - 20, 400); //RangeSlider ValueChange event slider.ValueChange += (sender, e) => { nfloat Value = e.Value; }; //RangeSlider RangeChagne event slider.RangeValueChange += (sender, e) => { nfloat RangeStart = e.RangeStart; nfloat RangeEnd = e.RangeEnd; }; slider.Delegate =new RangeSliderDelegate(); this.View.AddSubview(slider); // Perform any additional setup after loading the view, typically from a nib. } public override void DidReceiveMemoryWarning() { base.DidReceiveMemoryWarning(); // Release any cached data, images, etc that aren't in use. } } public class RangeSliderDelegate : SFRangeSliderDelegate { public override void ValueChange(SFRangeSlider SFRangeSlider, nfloat value) { nfloat Value = value; } public override void RangeValueChange(SFRangeSlider SFRangeSlider, nfloat start, nfloat end) { nfloat RangeStart = start; nfloat RangeEnd = end; } }
}
Step 3: Remove the Delegate API and the Delegate class from the sample.
namespace DelegateToEvent{ public partial class ViewController : UIViewController { protected ViewController(IntPtr handle) : base(handle) { // Note: this .ctor should not contain any initialization logic. } public override void ViewDidLoad() { base.ViewDidLoad(); SFRangeSlider slider = new SFRangeSlider(); slider.Frame = new CoreGraphics.CGRect(10, 50, this.View.Frame.Width-20,400); //RangeSlider ValueChange event slider.ValueChange += (sender, e) => { nfloat Value = e.Value; }; //RangeSlider RangeChagne event slider.RangeValueChange += (sender, e) => { nfloat RangeStart = e.RangeStart; nfloat RangeEnd = e.RangeEnd; }; this.View.AddSubview(slider); // Perform any additional setup after loading the view, typically from a nib. } public override void DidReceiveMemoryWarning() { base.DidReceiveMemoryWarning(); // Release any cached data, images, etc that aren't in use. } }}
Conclusion
I hope you enjoyed learning about how to handle events in RangeSlider of Xamarin.Forms platform.
You can refer to our Xamarin.Forms Range Slider feature tour page to know about its other groundbreaking feature representations and documentation, and how to quickly get started for configuration specifications.
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