Navigation:  I Want To... > Basics > Add validation to an application component

Use Case

Relevant Architecture

Relevant Types

Sample Code

using System;
using System.IO;
using ClearCanvas.Common;
using ClearCanvas.Desktop;
using ClearCanvas.Desktop.Actions;
using ClearCanvas.Desktop.Tools;
using ClearCanvas.Desktop.Validation;
 
namespace MyPlugin.TextEditor
{
   [ExtensionPoint()]
   public class TextEditorComponentViewExtensionPoint : ExtensionPoint<IApplicationComponentView> {}
 
   [AssociateView(typeof (TextEditorComponentViewExtensionPoint))]
   public class TextEditorComponent : ApplicationComponent
   {
      private string _filename;
      private string _text;
      private int _wordCount;
 
      public TextEditorComponent()
      {
      }
 
      [ValidateRegex("[<>]", SuccessOnMatch = false, Message = "Cannot have < or > characters.")]
      public string Filename
      {
         get { return _filename; }
         set
         {
            _filename = value;
            this.Modified = true;
         }
      }
 
      public string Text
      {
         get { return _text; }
         set
         {
            _text = value;
            this.Modified = true;
            UpdateWordCount();
         }
      }
 
      public int WordCount
      {
         get { return _wordCount; }
         private set
         {
            _wordCount = value;
            NotifyPropertyChanged("WordCount");
         }
      }
 
      public void Save()
      {
         if (base.HasValidationErrors)
         {
            base.ShowValidation(true);
         }
         else
         {
            File.WriteAllText(_filename, _text);
            this.Exit(ApplicationComponentExitCode.Accepted);
         }
      }
 
      public void Cancel()
      {
         this.Exit(ApplicationComponentExitCode.None);
      }
 
      private void UpdateWordCount()
      {
         // really simple algorithm to count words for illustrative purposes only
         // by assuming spaces, period, comma, or (semi)colon between words
         char[] wordSeparators = new char[] {' ', '.', ',', ';', ':'};
         int wordCount = this.Text.Split(wordSeparators, StringSplitOptions.RemoveEmptyEntries).Length;
         this.WordCount = wordCount;
      }
   }
}

Remarks

The above code sample is based on the Adding validation sub-section in Designing an Application Component.  Please consult the aforementioned section for a more thorough discussion on application component validation.

Examples in Code Base