/// <summary>
/// Creates a Where method call expression to be invoked on an expression e.g. (parameter, member, method call) of type IQueryable<T>.
/// </summary>
/// <typeparam name="TSource"></typeparam>
/// <param name="expression"></param>
/// <param name="filterGroup"></param>
/// <param name="parameterName"></param>
/// <returns></returns>
public static MethodCallExpression GetWhere <TSource>(this Expression expression, DataSource.FilterGroup filterGroup) where TSource : class
{
LambdaExpression filterExpression = filterGroup.GetFilterExpression <TSource>();
Type[] genericArgumentsForMethod = new Type[] { typeof(TSource) };
return(Expression.Call(typeof(Queryable), "Where", genericArgumentsForMethod, expression, filterExpression));
}
/// <summary>
/// Creates a Where lambda expression from a filter group
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="group"></param>
/// <returns></returns>
public static Expression <Func <IQueryable <T>, IQueryable <T> > > BuildWhereExpression <T>(this DataSource.FilterGroup group) where T : class
{
if (group == null)
{
return(null);
}
ParameterExpression param = Expression.Parameter(typeof(IQueryable <T>), "q");
MethodCallExpression mce = param.GetWhere <T>(group);
return(Expression.Lambda <Func <IQueryable <T>, IQueryable <T> > >(mce, param));
}
