public static IStringFilterOperator CreateFilterOperatorRule(StringFilterOperator filterOp, string value)
{
switch (filterOp)
{
case StringFilterOperator.Contains:
return(new ContainsOperator {
Value = value
});
case StringFilterOperator.Equals:
return(new EqualsOperator {
Value = value
});
case StringFilterOperator.NotContains:
return(new NotContainsOperator {
Value = value
});
case StringFilterOperator.StartsWith:
return(new StartsWithOperator {
Value = value
});
case StringFilterOperator.EndwsWith:
return(new EndsWithOperator {
Value = value
});
case StringFilterOperator.NotEquals:
return(new NotEqualsOperator {
Value = value
});
case StringFilterOperator.NotIsEmpty:
return(new NotIsEmptyOperator {
Value = value
});
case StringFilterOperator.IsEmpty:
return(new IsEmptyOperator());
default:
throw new Exception("Invalid Rule");
}
}
public static Expression <Func <T, bool> > BuildFilterExpression <T>(string propertyName, object propertyValue, StringFilterOperator op = StringFilterOperator.Equals)
{
var parameterExp = Expression.Parameter(typeof(T), typeof(T).ToString());
MemberExpression propertyExp;
if (propertyName.Contains('.'))
{
var propSplit = propertyName.Split('.');
propertyExp = Expression.PropertyOrField(Expression.PropertyOrField(parameterExp, propSplit[0]), propSplit[1]);
}
else
{
propertyExp = Expression.PropertyOrField(parameterExp, propertyName);
}
switch (op)
{
case StringFilterOperator.StartsWith:
case StringFilterOperator.EndsWith:
case StringFilterOperator.Contains:
{
MethodInfo method = typeof(string).GetMethod(op.ToString(), new[] { typeof(string) });
var someValue = Expression.Constant(propertyValue, typeof(string));
var methodExp = Expression.Call(propertyExp, method, someValue);
return(Expression.Lambda <Func <T, bool> >(methodExp, parameterExp));
}
case StringFilterOperator.Equals:
{
var bodyExp = Expression.Equal(propertyExp, Expression.Constant(propertyValue));
return(Expression.Lambda <Func <T, bool> >(bodyExp, parameterExp));
}
}
return(null);
}
