internal FromExpression(EngineType engineType)
{
_expressionContext = new SQLExpressionVisitorContenxt(engineType)
{
ParamPlaceHolderPrefix = SqlHelper.ParameterizedChar + "f__"
};
}
private static object VisitLambda(LambdaExpression lambda, SQLExpressionVisitorContenxt context)
{
if (lambda.Body.NodeType == ExpressionType.MemberAccess && context.Seperator == " ")
{
MemberExpression m = (MemberExpression)lambda.Body;
if (m.Expression != null)
{
object r = VisitMemberAccess(m, context);
if (!(r is PartialSqlString))
{
return(r);
}
if (!m.Expression.Type.IsValueType)
{
return(r.ToString() !);
}
//return $"{r}={context.DatabaesEngine.GetDbValueStatement(true, needQuoted: true)}";
return($"{r}=1");
}
}
return(Visit(lambda.Body, context));
}
private static object VisitBinary(BinaryExpression b, SQLExpressionVisitorContenxt context)
{
object left;
object right;
bool rightIsNull;
string operand = BindOperant(b.NodeType);
if (operand == "AND" || operand == "OR")
{
if (b.Left is MemberExpression m && m.Expression != null && m.Expression.NodeType == ExpressionType.Parameter)
{
//left = new PartialSqlString(string.Format(GlobalSettings.Culture, "{0}={1}", VisitMemberAccess(m, context), context.DatabaesEngine.GetDbValueStatement(true, needQuoted: true)));
left = new PartialSqlString($"{VisitMemberAccess(m, context)}=1");
}
else
{
left = Visit(b.Left, context);
}
if (b.Right is MemberExpression mm && mm.Expression != null && mm.Expression.NodeType == ExpressionType.Parameter)
{
right = new PartialSqlString($"{VisitMemberAccess(mm, context)}=1");
}
public static object Visit(Expression?exp, SQLExpressionVisitorContenxt context)
{
if (exp == null)
{
return(string.Empty);
}
switch (exp.NodeType)
{
case ExpressionType.Lambda:
return(VisitLambda((LambdaExpression)exp, context));
case ExpressionType.MemberAccess:
return(VisitMemberAccess((MemberExpression)exp, context));
case ExpressionType.Constant:
return(VisitConstant((ConstantExpression)exp));
case ExpressionType.Add:
case ExpressionType.AddChecked:
case ExpressionType.Subtract:
case ExpressionType.SubtractChecked:
case ExpressionType.Multiply:
case ExpressionType.MultiplyChecked:
case ExpressionType.Divide:
case ExpressionType.Modulo:
case ExpressionType.And:
case ExpressionType.AndAlso:
case ExpressionType.Or:
case ExpressionType.OrElse:
case ExpressionType.LessThan:
case ExpressionType.LessThanOrEqual:
case ExpressionType.GreaterThan:
case ExpressionType.GreaterThanOrEqual:
case ExpressionType.Equal:
case ExpressionType.NotEqual:
case ExpressionType.Coalesce:
case ExpressionType.ArrayIndex:
case ExpressionType.RightShift:
case ExpressionType.LeftShift:
case ExpressionType.ExclusiveOr:
return(VisitBinary((BinaryExpression)exp, context));
case ExpressionType.Negate:
case ExpressionType.NegateChecked:
case ExpressionType.Not:
case ExpressionType.Convert:
case ExpressionType.ConvertChecked:
case ExpressionType.ArrayLength:
case ExpressionType.Quote:
case ExpressionType.TypeAs:
return(VisitUnary((UnaryExpression)exp, context));
case ExpressionType.Parameter:
return(VisitParameter((ParameterExpression)exp));
case ExpressionType.Call:
return(VisitMethodCall((MethodCallExpression)exp, context));
case ExpressionType.New:
return(VisitNew((NewExpression)exp, context));
case ExpressionType.NewArrayInit:
case ExpressionType.NewArrayBounds:
return(VisitNewArray((NewArrayExpression)exp, context));
case ExpressionType.MemberInit:
return(VisitMemberInit((MemberInitExpression)exp));
default:
return(exp.ToString());
}
}
