private static BinaryExpression GetExpression <T>
(ParameterExpression param, FilterEngine filter1, FilterEngine filter2)
{
Expression bin1 = GetExpression <T>(param, filter1);
Expression bin2 = GetExpression <T>(param, filter2);
return(Expression.AndAlso(bin1, bin2));
}
public FilterEngine CreateFilterByOp(Control controlType, string propertyName, Op operation, string value)
{
FilterEngine filter = null;
switch (operation)
{
case Op.Equals:
case Op.GreaterThan:
case Op.GreaterThanOrEqual:
case Op.LessThanOrEqual:
case Op.LessThan:
case Op.NotEquals:
filter = new FilterEngine
{
PropertyName = propertyName,
Operation = operation
};
switch (controlType.GetType().Name)
{
case "TextBox":
filter.Value = Convert.ToInt32(value);
break;
}
break;
case Op.Contains:
case Op.StartsWith:
case Op.EndsWith:
filter = new FilterEngine
{
PropertyName = propertyName,
Operation = operation,
Value = value
};
break;
}
return(filter);
}
public FilterEngine GetFilterByPropertyType(PropertyInfo prop, string text)
{
FilterEngine filter = new FilterEngine {
PropertyName = prop.Name.ToLower()
};
switch (prop.PropertyType.ToString())
{
case "System.Int32":
filter.Operation = Op.Equals;
if (text.IsDigitsOnly())
{
filter.Value = Convert.ToInt32(text);
}
else
{
filter.Value = -1;
}
break;
case "System.String":
filter.Operation = Op.Contains;
filter.Value = text.ToLower();
break;
case "global::System.DateTime":
filter.Operation = Op.LessThanOrEqual;
filter.Value = text;
break;
case "System.Double":
filter.Operation = Op.Equals;
if (text.IsDigitsOnly())
{
filter.Value = Convert.ToDouble(text);
}
else
{
filter.Value = -1;
}
break;
case "System.Nullable`1[System.Boolean]":
case "System.Boolean":
filter.Operation = Op.Equals;
Boolean parsedValue;
if (Boolean.TryParse(text.YesNoByBooleanValue(), out parsedValue))
{
filter.Value = parsedValue;
}
else
{
filter.Value = "false";
}
break;
}
return(filter);
}
private static Expression GetExpression <T>(ParameterExpression param, FilterEngine filter)
{
var propertyName = filter.PropertyName.ToLower();
MemberExpression member = Expression.Property(param, propertyName);
string filterValue = filter.Value.ToString().ToLower();
UnaryExpression constant;
if (member.Type == typeof(Int32?) || member.Type == typeof(Int32))
{
constant = Expression.Convert(Expression.Constant(Int32.Parse(filterValue)), member.Type);
}
else if (member.Type == typeof(DateTime?) || member.Type == typeof(DateTime))
{
constant = Expression.Convert(Expression.Constant(DateTime.Parse(filterValue)), member.Type);
}
else if (member.Type == typeof(Guid?) || member.Type == typeof(Guid))
{
constant = Expression.Convert(Expression.Constant(Guid.Parse(filterValue)), member.Type);
}
else if (member.Type == typeof(Boolean?) || member.Type == typeof(Boolean))
{
constant = Expression.Convert(Expression.Constant(Boolean.Parse(filterValue)), member.Type);
}
else
{
constant = Expression.Convert(Expression.Constant(filterValue), member.Type);
}
switch (filter.Operation)
{
case Op.Equals:
if (member.Type.Name == "String")
{
var expToLower = Expression.Call(member, ToLowerMethod);
return(Expression.Equal(expToLower, constant));
}
return(Expression.Equal(member, constant));
case Op.GreaterThan:
return(Expression.GreaterThan(member, constant));
case Op.GreaterThanOrEqual:
return(Expression.GreaterThanOrEqual(member, constant));
case Op.LessThan:
return(Expression.LessThan(member, constant));
case Op.LessThanOrEqual:
return(Expression.LessThanOrEqual(member, constant));
case Op.Contains:
var expToLowerContains = Expression.Call(member, ToLowerMethod);
return(Expression.Call(expToLowerContains, ContainsMethod, constant)); // call StartsWith() on the exp, which is property.ToLower()
case Op.StartsWith:
var expToLowerStartsWith = Expression.Call(member, ToLowerMethod);
return(Expression.Call(expToLowerStartsWith, StartsWithMethod, constant));
case Op.EndsWith:
var expToLowerEndsWith = Expression.Call(member, ToLowerMethod);
return(Expression.Call(expToLowerEndsWith, EndsWithMethod, constant));
case Op.NotEquals:
if (member.Type.Name == "String")
{
var expToLowerNotEqual = Expression.Call(member, ToLowerMethod);
return(Expression.NotEqual(expToLowerNotEqual, constant));
}
else
{
return(Expression.NotEqual(member, constant));
}
}
return(null);
}