static CustomExpressionTree ProcessWhereStr(string whereStr)
{
var result = new CustomExpressionTree();
var junctionIndex = new List <Tuple <int, string> >();
var index2 = 0;
GetJunctionSort(whereStr, junctionIndex);
var singleExps = whereStr.Split(junctionSplit, StringSplitOptions.RemoveEmptyEntries).ToList().Select(x => x.Replace(" ", "")).Where(x => x != "");
foreach (var expression in singleExps)
{
var singleExp = expression.Split(OperSplit, StringSplitOptions.RemoveEmptyEntries).ToList().Select(x => x.Replace(" ", "")).ToArray();
var subExp = new CustomExpression {
ParameterName = singleExp[0], ParameterValue = singleExp[1]
};
var op = expression.Remove(expression.Length - singleExp[1].Length); //tail
op = op.Remove(0, singleExp[0].Length); // header
subExp.Op = op; //operation in middle
ProcessSubExp(subExp, result);
if (index2 < junctionIndex.Count)
{
var oper = junctionIndex[index2];
var item2 = oper.Item2;
result.Push(item2);
}
index2++;
}
return(result);
}
static void ProcessExp <TObj>(Expression pe, CustomExpression currExpress, IList <int> flagArr, IList <BinaryExpression> expressionList)
{
var leftPart = Expression.Property(pe, typeof(TObj).GetProperty(currExpress.ParameterName));
var typ = typeof(TObj).GetProperty(currExpress.ParameterName).PropertyType;
var constCondition = Expression.Constant(System.Convert.ChangeType(currExpress.ParameterValue, typ), typ);
CreateExpByOp(currExpress, expressionList, leftPart, constCondition);
var lastFlag = (int)ConstJunction.Flag.NULL;
if (flagArr.Count - 1 >= 0)
{
lastFlag = flagArr[flagArr.Count - 1];
}
if (lastFlag != (int)ConstJunction.Flag.NULL && lastFlag != (int)ConstJunction.Flag.Or && lastFlag != (int)ConstJunction.Flag.And)
{
flagArr.RemoveAt(flagArr.Count - 1);
}
}
static void ProcessSubExp(CustomExpression subExp, CustomExpressionTree result)
{
var index = 0;
do
{
index = subExp.ParameterName.IndexOf(ConstBrace.LeftBrace);
if (index < 0)
{
break;
}
result.Push(ConstBrace.LeftBrace);
subExp.ParameterName = subExp.ParameterName.Remove(index, 1);
} while (index >= 0);
var flagEnd = false;
var cntRightBrace = 0;
index = 0;
do
{
index = subExp.ParameterValue.IndexOf(ConstBrace.RightBrace);
if (index < 0)
{
break;
}
cntRightBrace++;
subExp.ParameterValue = subExp.ParameterValue.Remove(index, 1);
flagEnd = true;
} while (index >= 0);
result.Push(subExp);
if (flagEnd)
{
while (cntRightBrace-- > 0)
{
result.Push(ConstBrace.RightBrace);
}
}
}
static void CreateExpByOp(CustomExpression currExpress, IList <BinaryExpression> expressionList, MemberExpression subLeft, ConstantExpression condition)
{
switch (currExpress.Op)
{
case ConstOper.GreaterEqual:
expressionList.Add(Expression.GreaterThanOrEqual(subLeft, condition));
break;
case ConstOper.LessEqual:
expressionList.Add(Expression.LessThanOrEqual(subLeft, condition));
break;
case ConstOper.Equal:
expressionList.Add(Expression.Equal(subLeft, condition));
break;
case ConstOper.NoEqual:
expressionList.Add(Expression.NotEqual(subLeft, condition));
break;
}
}