private void SetPropertyExpression(ExpressionInfo expressionInfo, string expressionTokenText)
{
PropertyExpression = ExpressionParserHelper.GetPropertyExpression(
expressionInfo.Parameter, expressionInfo.ParameterSyntax, expressionTokenText);
PropertyInfo = (PropertyInfo)this.PropertyExpression.Member;
if (PropertyInfo.PropertyType == typeof(bool))
{
Expression = Expression.IsTrue(this.PropertyExpression);
}
}
public void Update(
ExpressionInfo expressionInfo,
string expressionTokenText)
{
if (ExpressionParserHelper.IsPropertyToken(expressionInfo.ParameterSyntax, expressionTokenText))
{
SetPropertyExpression(expressionInfo, expressionTokenText);
return;
}
if (OperationExpression != null)
{
var constantValue = expressionTokenText;
if (PropertyInfo.PropertyType == typeof(string))
{
constantValue = constantValue.Replace("'", null);
}
var comparisonConstantValue =
TypeDescriptor
.GetConverter(PropertyInfo.PropertyType)
.ConvertFromString(constantValue);
Expression =
OperationExpression(PropertyExpression, Expression.Constant(comparisonConstantValue));
return;
}
if (ExpressionParserHelper.GetOperatorFunc(expressionTokenText) != null)
{
OperationExpression = ExpressionParserHelper.GetOperatorFunc(expressionTokenText);
}
}
public Expression <Func <T, bool> > Parse <T>(string evalExpression)
{
var expressionInfo =
ExpressionInfo.Create <T>(evalExpression);
var expressionBuilder =
new ExpressionBuilder(expressionInfo);
var expressionTokens = new List <Expression>();
var logicOperatorTokens = new List <string>();
var token = TokenToSkip;
while (!EndOfTokens(expressionInfo, token))
{
var expressionResult =
expressionBuilder.Parse(token);
token += expressionResult.TokensParsed;
expressionTokens.Add(expressionResult.Expression);
if (EndOfTokens(expressionInfo, token))
{
break;
}
var expressionText = expressionInfo.Tokens[token];
if (ExpressionParserHelper.IsLogicToken(expressionText))
{
logicOperatorTokens.Add(expressionText);
}
token++;
}
var logicOperatorIndex = 0;
Expression expression = null;
for (var index = 0; index < expressionTokens.Count; index++)
{
if (index == 0)
{
continue;
}
var logicFunc =
ExpressionParserHelper
.GetLogicExpression(logicOperatorTokens[logicOperatorIndex]);
expression =
logicFunc(expressionTokens[index - 1], expressionTokens[index]);
logicOperatorIndex++;
}
if (expression == null)
{
expression = expressionTokens.Single();
}
return
(Expression.Lambda <Func <T, bool> >(expression, expressionInfo.Parameter));
}
