检查SqlDataReader列是否存在（扩展方法）

Posted 2021-02-25

This snippet is "extension method" for IDataReader.
You can use this snippet below ;
I assume you have datareader like that
SqlDataReader dataReader = command.ExecuteReader();

if (dataReader.IsColumnExists("columnName"))
{
//do something
}


and also you should validation null value control if you work critical datas

if (dataReader.IsColumnExists("columName"))
{
if (dataReader["columName"] != DBNull.Value)
{
//do something
}
}

public static bool IsColumnExists(this IDataReader dataReader, string columnName)
        {
            bool retVal = false;
 
            try
            {
                dataReader.GetSchemaTable().DefaultView.RowFilter = string.Format("ColumnName= '{0}'", columnName);
                if (dataReader.GetSchemaTable().DefaultView.Count > 0)
                {
                    retVal = true;
                }
            }
 
            catch (Exception ex)
            {
 
                throw;
            }
 
            return retVal;
        }