Question

I’ve got a method that returns a List for a DataSet table

public static List<string> GetListFromDataTable(DataSet dataSet, string tableName, string rowName)
    {
        int count = dataSet.Tables[tableName].Rows.Count;
        List<string> values = new List<string>();

        // Loop through the table and row and add them into the array
        for (int i = 0; i < count; i++)
        {
            values.Add(dataSet.Tables[tableName].Rows[i][rowName].ToString());
        }
        return values;
    }

Is there a way I can dynamically set the datatype for the list and have this one method cater for all datatypes so I can specify upon calling this method that it should be a List<int> or List<string> or List<AnythingILike>?

Also, what would the return type be when declaring the method?

Thanks in advance,
Brett

Answer 1

Make your method generic:

public static List<T> GetListFromDataTable<T>(DataSet dataSet, string tableName, string rowName)
{
    // Find out how many rows are in your table and create an aray of that length
    int count = dataSet.Tables[tableName].Rows.Count;
    List<T> values = new List<T>();

    // Loop through the table and row and add them into the array
    for (int i = 0; i < count; i++)
    {
        values.Add((T)dataSet.Tables[tableName].Rows[i][rowName]);
    }
    return values;
}

Then to call it:

List<string> test1 = GetListFromDataTable<string>(dataSet, tableName, rowName);
List<int> test2 = GetListFromDataTable<int>(dataSet, tableName, rowName);
List<Guid> test3 = GetListFromDataTable<Guid>(dataSet, tableName, rowName);