How to Dynamically Order IQueryable Using a String Column Name?

OrderBy using string column name on IQueryable in generic extension method

When using OrderBy to sort a query, you must specify the type of sort expression. However, in some cases the type may not be known at compile time, making it challenging to apply sorting using string column names.

To overcome this problem, we can create a generic extension method that receives the column name as a string and dynamically generates the sort expression based on reflection. The following is the modified code version:

<code class="language-csharp">public static IQueryable<T> ApplySortFilter<T>(this IQueryable<T> query, string columnName)
{
    var type = typeof(T);
    var property = type.GetProperty(columnName);
    var parameter = Expression.Parameter(type, "o");
    var propertyAccess = Expression.MakeMemberAccess(parameter, property);
    var sortExpression = Expression.Lambda(propertyAccess, parameter);
    return query.OrderBy(sortExpression);
}</code>

This updated code uses reflection to retrieve properties based on the provided column names, creating a dynamic sort expression. You can now use it as follows:

<code class="language-csharp">var sortedQuery = query.ApplySortFilter("ColumnName");</code>

Where "ColumnName" is the name of the column to be sorted.

As suggested in the provided answer, another approach is to use a custom extension method that accepts the type and sorting expression as parameters:

<code class="language-csharp">public static IQueryable<T> OrderBy<T>(this IQueryable<T> source, string ordering, params object[] values)
{
    var type = typeof(T);
    // ... (其余代码与之前相同)
}</code>

This method can be used as follows:

<code class="language-csharp">var sortedQuery = query.OrderBy<T>("ColumnName");</code>

By using either of these two methods, you can dynamically apply sorting to an IQueryable using string column names, regardless of the underlying type.

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