C# AsExpression类代码示例

			public override void VisitAsExpression (AsExpression asExpression)
			{
				base.VisitAsExpression (asExpression);

				VisitTypeCastExpression (asExpression, ctx.Resolve (asExpression.Expression).Type,
					ctx.ResolveType (asExpression.Type));
			}

			public override void VisitAsExpression (AsExpression asExpression)
			{
				base.VisitAsExpression (asExpression);

				CheckTypeCast (asExpression, asExpression.Expression, asExpression.Expression.EndLocation,
					asExpression.EndLocation);
			}

 public override void VisitAsExpression(AsExpression asExpression)
 {
     if (InsertParenthesesForReadability) {
         // few people know the precedence of 'as', so always put parentheses in nice-looking mode.
         ParenthesizeIfRequired(asExpression.Expression, Primary);
     } else {
         ParenthesizeIfRequired(asExpression.Expression, RelationalAndTypeTesting);
     }
     base.VisitAsExpression(asExpression);
 }

		public void VisitAsExpression(AsExpression asExpression)
		{
			StartNode(asExpression);
			asExpression.Expression.AcceptVisitor(this);
			Space();
			WriteKeyword(AsExpression.AsKeywordRole);
			Space();
			asExpression.Type.AcceptVisitor(this);
			EndNode(asExpression);
		}

			public override object Visit (As asExpression)
			{
				var result = new AsExpression ();
				result.AddChild ((INode)asExpression.Expr.Accept (this), AsExpression.Roles.Expression);
				result.AddChild (new CSharpTokenNode (Convert (asExpression.Location), "as".Length), AsExpression.Roles.Keyword);
				result.AddChild ((INode)asExpression.ProbeType.Accept (this), AsExpression.Roles.ReturnType);
				return result;
			}

		public virtual void VisitAsExpression (AsExpression asExpression)
		{
			VisitChildren (asExpression);
		}

			public override object Visit(As asExpression)
			{
				var result = new AsExpression();
				if (asExpression.Expr != null)
					result.AddChild((Expression)asExpression.Expr.Accept(this), Roles.Expression);
				result.AddChild(new CSharpTokenNode(Convert(asExpression.Location), AsExpression.AsKeywordRole), AsExpression.AsKeywordRole);
				if (asExpression.ProbeType != null)
					result.AddChild(ConvertToType(asExpression.ProbeType), Roles.Type);
				return result;
			}

 public virtual void VisitAsExpression(AsExpression asExpression)
 {
     if (this.ThrowException)
     {
         throw (Exception)this.CreateException(asExpression);
     }
 }

        /// <summary>
        /// Reads an as expression.
        /// </summary>
        /// <param name="leftHandSide">The expression on the left hand side of the operator.</param>
        /// <param name="previousPrecedence">The precedence of the expression just before this one.</param>
        /// <param name="unsafeCode">Indicates whether the code being parsed resides in an unsafe code block.</param>
        /// <returns>Returns the expression.</returns>
        private AsExpression GetAsExpression(
            Expression leftHandSide, ExpressionPrecedence previousPrecedence, bool unsafeCode)
        {
            Param.AssertNotNull(leftHandSide, "leftHandSide");
            Param.Ignore(previousPrecedence);
            Param.Ignore(unsafeCode);

            AsExpression expression = null;

            // Check the previous precedence to see if we are allowed to gather up the as expression.
            if (this.CheckPrecedence(previousPrecedence, ExpressionPrecedence.Relational))
            {
                // Make sure the left hand side has at least one token.
                Debug.Assert(leftHandSide.Tokens.First != null, "The left hand side should not be empty");

                // Get the as symbol.
                this.tokens.Add(this.GetToken(CsTokenType.As, SymbolType.As));

                // The next token must be the type.
                this.GetNextSymbol(SymbolType.Other);

                // Get the expression representing the type.
                LiteralExpression rightHandSide = this.GetTypeTokenExpression(unsafeCode, true, true);
                if (rightHandSide == null || rightHandSide.Tokens.First == null)
                {
                    throw this.CreateSyntaxException();
                }

                // Create the partial token list for the expression.
                CsTokenList partialTokens = new CsTokenList(this.tokens, leftHandSide.Tokens.First, this.tokens.Last);

                // Create and return the expression.
                expression = new AsExpression(partialTokens, leftHandSide, rightHandSide);
            }

            return expression;
        }

 public StringBuilder VisitAsExpression(AsExpression asExpression, int data)
 {
     throw new SLSharpException("SL# does not have reflection-supported casts.");
 }

 public CastBlock(IEmitter emitter, AsExpression asExpression)
     : base(emitter, asExpression)
 {
     this.Emitter = emitter;
     this.AsExpression = asExpression;
 }

		public void VisitAsExpression(AsExpression asExpression)
		{
			StartNode(asExpression);
			LPar ();
			LPar ();
			asExpression.Expression.AcceptVisitor(this);
			Space();
			WriteKeyword("instanceof", AsExpression.AsKeywordRole);
			Space();
			asExpression.Type.AcceptVisitor(this);
			EndNode(asExpression);
			RPar ();
			WriteToken ("?<", Roles.Expression);
			asExpression.Type.AcceptVisitor(this);
			WriteToken (">", Roles.Expression);
			asExpression.Expression.AcceptVisitor(this);
			WriteToken (":null", Roles.Expression);
			RPar ();
		}

 public override void VisitAsExpression(AsExpression asExpression)
 {
     new CastBlock(this, asExpression).Emit();
 }

 public void VisitAsExpression(AsExpression asExpression)
 {
     JsonObject expression = CreateJsonExpression(asExpression);
     AddKeyword(expression, AsExpression.AsKeywordRole);
     expression.AddJsonValue("type-info", GenTypeInfo(asExpression.Type));
     Push(expression);
 }

 public void VisitAsExpression(AsExpression node)
 {
     NotSupported(node);
 }