Xamarin SignaturePad：代码生成视图设置签名点后长度为0问题咨询

Hey there! Let's figure out why your code-generated SignaturePadView is showing an empty Points array after assignment—this is a common gotcha with dynamic control creation, so let's break down the likely missing steps:

• Wait for the control to finish initializing
  When you create a SignaturePadView via code, it hasn't gone through the full XAML control lifecycle yet (like the Loaded event). If you set Points immediately after instantiation, the control might not be ready to accept the data. Try hooking into the Loaded event to assign the points once the control is fully initialized:

  var signaturePad = new SignaturePadView();
  // Set basic dimensions first (critical for layout!)
  signaturePad.Width = 400;
  signaturePad.Height = 200;
  
  signaturePad.Loaded += (sender, e) => {
      signaturePad.Points = points;
      // Optional: Force a redraw to ensure the signature renders
      signaturePad.InvalidateVisual();
  };
  
  // Don't forget to add the control to your parent layout container!
  yourParentPanel.Children.Add(signaturePad);
  

• Use the correct collection type for Points
  Some versions of SignaturePad require Points to be an ObservableCollection<Point> instead of a plain array or List<Point>. If your points variable is a basic array/list, convert it to the proper type:

  signaturePad.Points = new ObservableCollection<Point>(points);
  

• Ensure the control has explicit dimensions
  Code-generated controls often default to zero size if you don't set Width and Height. Without proper layout bounds, the control might discard the points or fail to render them. Always set explicit dimensions before adding the control to your layout.

• Verify your source points data
  Double-check that the points array you're pulling from the database isn't empty or corrupted. A quick debug check like Debug.WriteLine($"Points count: {points.Length}") can rule out bad data as the cause.

If you try these steps and still run into issues, it might help to check if you're using the latest version of the SignaturePad library—sometimes bugs around dynamic control initialization get fixed in newer releases.

内容的提问来源于stack exchange，提问作者Shaun Bauer