mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/View/BreadCrumbTextConverter.cs

   1 //------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation.View
   6 {
   7     using System.Windows.Data;
   8     using System.Activities.Presentation.Model;
   9
  10     internal class BreadCrumbTextConverter : IMultiValueConverter
  11     {
  12         const int MaxDisplayNameLength = 20;
  13         double pixelsPerChar = 6.5;
  14
  15         internal double PixelsPerChar
  16         {
  17             get { return this.pixelsPerChar; }
  18             set { this.pixelsPerChar = Math.Max(5.0, value); }
  19         }
  20
  21         public object Convert(object[] values, Type targetType, object parameter, System.Globalization.CultureInfo culture)
  22         {
  23             int actualDisplayNameLength = MaxDisplayNameLength;
  24             ModelItem boundModelItem = values[0] as ModelItem;
  25
  26             // default to root item's typename
  27             string breadCrumbText = (null != boundModelItem ? boundModelItem.ItemType.Name : "<null>");
  28             // if there is a display name property on root use that as the file name.
  29             if (values[1] is ModelItem)
  30             {
  31                 ModelItem displayNameProperty = (ModelItem)values[1];
  32                 if (typeof(string) == displayNameProperty.ItemType)
  33                 {
  34                     values[1] = displayNameProperty.GetCurrentValue();
  35                 }
  36             }
  37             if (values[1] is string)
  38             {
  39                 string displayName = (string)values[1];
  40                 if (!displayName.Equals(string.Empty))
  41                 {
  42                     breadCrumbText = displayName;
  43                 }
  44             }
  45             if (values.Length == 3 && values[2] is double)
  46             {
  47                 double actualControlWidth = (double)values[2];
  48                 actualDisplayNameLength = (int)Math.Max(MaxDisplayNameLength, actualControlWidth / pixelsPerChar);
  49
  50             }
  51             if (breadCrumbText.Length > actualDisplayNameLength)
  52             {
  53                 breadCrumbText = breadCrumbText.Substring(0, actualDisplayNameLength - 3) + "...";
  54             }
  55             return breadCrumbText;
  56         }
  57
  58         public object[] ConvertBack(object value, Type[] targetTypes, object parameter, System.Globalization.CultureInfo culture)
  59         {
  60             throw FxTrace.Exception.AsError(new InvalidOperationException());
  61         }
  62     }
  63 }