-

Src/Asp.Net/SqlServerTest/UnitTest/ExpressionTest/Method.cs

@@ -725,18 +725,15 @@ namespace OrmTest.UnitTest
 
         private void IIF4()
         {
-            //Expression<Func<DataTestInfo2, bool>> exp = it => SqlFunc.IIF(true, it.Bool1, it.Bool2) == true;
-            //SqlServerExpressionContext expContext = new SqlServerExpressionContext();
-            //expContext.Resolve(exp, ResolveExpressType.WhereSingle);
-            //var value = expContext.Result.GetString();
-            //var pars = expContext.Parameters;
-            //base.Check(value, pars, "(( CASE  WHEN  ([Name] like '%'+@MethodConst0+'%')  THEN @MethodConst1  ELSE @MethodConst2 END ) = @Const3 )", new List<SugarParameter>()
-            //{
-            //         new SugarParameter("@MethodConst0","a"),
-            //         new SugarParameter("@MethodConst1",true),
-            //         new SugarParameter("@MethodConst2",false),
-            //                         new SugarParameter("@Const3",true)
-            //}, "IIF4 error");
+            Expression<Func<DataTestInfo2, bool>> exp = it => SqlFunc.IIF(true, it.Bool1, it.Bool2) == true;
+            SqlServerExpressionContext expContext = new SqlServerExpressionContext();
+            expContext.Resolve(exp, ResolveExpressType.WhereSingle);
+            var value = expContext.Result.GetString();
+            var pars = expContext.Parameters;
+            base.Check(value, pars, "(( CASE  WHEN ( 1 = 1 )  THEN [Bool1]  ELSE [Bool2] END ) = @Const0 )", new List<SugarParameter>()
+            {
+                     new SugarParameter("@Const0",true)
+            }, "IIF4 error");
         }
     }
 }

Src/Asp.Net/SqlSugar/ExpressionsToSql/ResolveItems/MethodCallExpressionResolve.cs

@@ -146,19 +146,33 @@ namespace SqlSugar
         private void AppendItem(ExpressionParameter parameter, string name, IEnumerable<Expression> args, MethodCallExpressionModel model, Expression item)
         {
             var isBinaryExpression = item is BinaryExpression || item is MethodCallExpression;
-            var isIFFBoolMember = name == "IIF" && (args.Last() is MemberExpression) && (args.Last() as MemberExpression).Type == PubConst.BoolType;
-            var isIFFUnary = name == "IIF" && (args.Last() is UnaryExpression) && (args.Last() as UnaryExpression).Operand.Type == PubConst.BoolType;
-            var isIFFBoolBinary = name == "IIF" && (args.Last() is BinaryExpression) && (args.Last() as BinaryExpression).Type == PubConst.BoolType;
-            if (isIFFUnary && item != args.First())
+            var isConst = item is ConstantExpression;
+            var isIIF= name == "IIF";
+            var isIFFBoolMember = isIIF && (item is MemberExpression) && (item as MemberExpression).Type == PubConst.BoolType;
+            var isIFFUnary = isIIF && (item is UnaryExpression) && (item as UnaryExpression).Operand.Type == PubConst.BoolType;
+            var isIFFBoolBinary = isIIF && (item is BinaryExpression) && (item as BinaryExpression).Type == PubConst.BoolType;
+            var isFirst = item == args.First();
+            if (isFirst&& isIIF && isConst)
+            {
+                var value = (item as ConstantExpression).Value.ObjToBool() ? this.Context.DbMehtods.True() : this.Context.DbMehtods.False();
+                var methodCallExpressionArgs = new MethodCallExpressionArgs()
+                {
+                    IsMember =true,
+                    MemberName = value,
+                    MemberValue= value
+                };
+                model.Args.Add(methodCallExpressionArgs);
+            }
+            else if (isIFFUnary && !isFirst)
             {
                 AppendModelByIIFMember(parameter, model, (item as UnaryExpression).Operand);
             }
-            else if (isIFFBoolMember && item != args.First())
+            else if (isIFFBoolMember && !isFirst)
             {
                 AppendModelByIIFMember(parameter, model, item);
 
             }
-            else if (isIFFBoolBinary && item != args.First())
+            else if (isIFFBoolBinary && !isFirst)
             {
                 AppendModelByIIFBinary(parameter, model, item);