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- 优化 表达式中不能使用 c# 函数的问题，

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> 如：where(a => HttpContext.Session.GetString("UserID") == a.UserId)
This commit is contained in:
28810
2019-07-29 10:27:39 +08:00
parent 4609c910dd
commit 256963907e
3 changed files with 27 additions and 2 deletions
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18
FreeSql/Extensions/LambadaExpressionExtensions.cs
View File

@ -86,6 +86,13 @@ namespace System.Linq.Expressions
var body = Expression.Not(exp.Body);
return Expression.Lambda<Func<T, bool>>(body, candidateExpr);
}
internal static bool IsParameter(this Expression exp)
{
var test = new TextParameterExpressionVisitor();
test.Visit(exp);
return test.Result;
}
}
internal class NewExpressionVisitor : ExpressionVisitor
@ -102,4 +109,15 @@ namespace System.Linq.Expressions
protected override Expression VisitParameter(ParameterExpression node) =>
node == _oldParameter ? this._newParameter : node;
}
internal class TextParameterExpressionVisitor : ExpressionVisitor
{
public bool Result { get; private set; }
protected override Expression VisitParameter(ParameterExpression node)
{
if (!Result) Result = true;
return node;
}
}
}

7
FreeSql/Internal/CommonExpression.cs
View File

@ -837,6 +837,7 @@ namespace FreeSql.Internal
//}
var other3Exp = ExpressionLambdaToSqlOther(exp3, tsc);
if (string.IsNullOrEmpty(other3Exp) == false) return other3Exp;
if (exp3.IsParameter() == false) return formatSql(Expression.Lambda(exp3).Compile().DynamicInvoke(), tsc.mapType);
throw new Exception($"未实现函数表达式 {exp3} 解析");
case ExpressionType.Parameter:
case ExpressionType.MemberAccess:
@ -1097,7 +1098,11 @@ namespace FreeSql.Internal
case ExpressionType.Coalesce:
return _common.IsNull(ExpressionLambdaToSql(expBinary.Left, tsc), ExpressionLambdaToSql(expBinary.Right, tsc));
}
if (dicExpressionOperator.TryGetValue(expBinary.NodeType, out var tryoper) == false) return "";
if (dicExpressionOperator.TryGetValue(expBinary.NodeType, out var tryoper) == false)
{
if (exp.IsParameter() == false) return formatSql(Expression.Lambda(exp).Compile().DynamicInvoke(), tsc.mapType);
return "";
}
return ExpressionBinary(tryoper, expBinary.Left, expBinary.Right, tsc);
}