mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/NonTextualExpressionMorphHelper.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation
   6 {
   7     using System;
   8     using System.Activities.Presentation.Expressions;
   9     using System.Activities.Presentation.Model;
  10     using System.Activities.Presentation.Services;
  11     using System.Activities.Presentation.View;
  12     using System.Collections.Generic;
  13     using System.Linq;
  14     using System.Runtime;
  15     using System.Text;
  16     using Microsoft.VisualBasic.Activities;
  17
  18     //This serves as expression morph helper for following non-textual expressions:
  19     //1) Literal<T>
  20     //2) VariableValue<T>/VariableReference<T>
  21     //The helper will morph these expressions to what specified at root object by ExpressionActivityEditor attached property
  22     class NonTextualExpressionMorphHelper : ExpressionMorphHelper
  23     {
  24         public override bool TryMorphExpression(ActivityWithResult expression, bool isLocationExpression, Type newType,
  25             EditingContext context, out ActivityWithResult newExpression)
  26         {
  27             Fx.Assert(expression != null, "Original expression shouldn't be null in morph helper");
  28             Fx.Assert(context != null, "EditingContext shouldn't be null in morph helper");
  29             newExpression = null;
  30             if (expression.ResultType == newType &&
  31                 (ExpressionHelper.IsGenericLocationExpressionType(expression) == isLocationExpression))
  32             {
  33                 newExpression = expression;
  34                 return true;
  35             }
  36
  37             if (context != null)
  38             {
  39                 string expressionEditor = ExpressionHelper.GetRootEditorSetting(context.Services.GetService<ModelTreeManager>(), WorkflowDesigner.GetTargetFramework(context));
  40                 ParserContext parserContext = new ParserContext();
  41                 string expressionText = ExpressionHelper.GetExpressionString(expression, parserContext);
  42                 if (!string.IsNullOrEmpty(expressionEditor))
  43                 {
  44                     return ExpressionTextBox.TryConvertFromString(expressionEditor, expressionText, isLocationExpression, newType, out newExpression);
  45                 }
  46             }
  47
  48             return false;
  49         }
  50     }
  51 }