internal static TypeCode TypeCodeFromType(Type type)
{
if (s_typeToTypeCodeMap == null)
{
lock (s_lock) {
if (s_typeToTypeCodeMap == null)
{
//
Dictionary <Type, TypeCode> typeNameToTypeCode = new Dictionary <Type, TypeCode>();
typeNameToTypeCode[typeof(Boolean)] = TypeCode.Boolean;
typeNameToTypeCode[typeof(String)] = TypeCode.String;
typeNameToTypeCode[typeof(Byte)] = TypeCode.Byte;
typeNameToTypeCode[typeof(Int16)] = TypeCode.Int16;
typeNameToTypeCode[typeof(Int32)] = TypeCode.Int32;
typeNameToTypeCode[typeof(Int64)] = TypeCode.Int64;
typeNameToTypeCode[typeof(Single)] = TypeCode.Single;
typeNameToTypeCode[typeof(Double)] = TypeCode.Double;
typeNameToTypeCode[typeof(Decimal)] = TypeCode.Decimal;
typeNameToTypeCode[typeof(DateTime)] = TypeCode.DateTime;
typeNameToTypeCode[typeof(Char)] = TypeCode.Char;
// We don't support columns of type 'sqlvariant', which show up as Object
//
typeNameToTypeCode[typeof(Object)] = TypeCode.DBNull;
// We don't support byte arrays. This include columns of type 'timestamp'
typeNameToTypeCode[typeof(Byte[])] = TypeCode.DBNull;
// Use Object for Guid's (though we need to do some special processing)
typeNameToTypeCode[typeof(Guid)] = TypeCode.Object;
s_typeToTypeCodeMap = typeNameToTypeCode;
}
}
}
// If it's an Nullable<T>, work with T instead
type = Misc.RemoveNullableFromType(type);
TypeCode typeCode;
if (s_typeToTypeCodeMap.TryGetValue(type, out typeCode))
{
return(typeCode);
}
return(TypeCode.Object);
}
public static IQueryable ApplyEqualityFilter(IQueryable source, string propertyName, object value)
{
ParameterExpression parameterExpression = Expression.Parameter(source.ElementType, String.Empty);
Expression propertyExpression = CreatePropertyExpression(parameterExpression, propertyName);
if (Nullable.GetUnderlyingType(propertyExpression.Type) != null && value != null)
{
propertyExpression = Expression.Convert(propertyExpression, Misc.RemoveNullableFromType(propertyExpression.Type));
}
value = Misc.ChangeType(value, propertyExpression.Type);
Expression compareExpression = Expression.Equal(propertyExpression, Expression.Constant(value));
LambdaExpression lambda = Expression.Lambda(compareExpression, parameterExpression);
MethodCallExpression whereCall = Expression.Call(typeof(Queryable), "Where", new Type[] { source.ElementType }, source.Expression, Expression.Quote(lambda));
return(source.Provider.CreateQuery(whereCall));
}
