C# SqlDataReader No data exists for the row/column

Log.WriteLine("Value of CompanyName column:" + thisReader["CompanyName"]); 

int resign = 0;
int not_resign = 0;
int resign_count = 0;
int not_resign_count = 0;

while (reader.Read())
{   
    if (Convert.ToInt32(reader["Resigned"]) == 1)
    {
        resign = Convert.ToInt32(reader["Sum"]);        
        resign_count = Convert.ToInt32(reader["Count"]);        
    }
    else
    {
        not_resign = Convert.ToInt32(reader["Sum"]);        
        not_resign_count = Convert.ToInt32(reader["Count"]);        
    } 
}

reader.GetString(0); //0 stands for "the 0'th column"

//This "while" iterates through all rows!
while(MysqlData.Read())
{   
    //This "for" iterates through each column of the current row!
    for (int i = 0; i < MysqlData.FieldCount; i++)
    {
        lRoom.Add(MysqlData.GetValue(i).ToString());
    }
}

  public static class DataRecordExtensions
        {
            public static bool HasColumn(this IDataRecord dr, string columnName)
            {
                for (int i=0; i < dr.FieldCount; i++)
                {
                    if (dr.GetName(i).Equals(columnName, StringComparison.InvariantCultureIgnoreCase))
                        return true;
                }
                return false;
            }
        }

public static bool HasColumn(DbDataReader Reader, string ColumnName) { 
    foreach (DataRow row in Reader.GetSchemaTable().Rows) { 
        if (row["ColumnName"].ToString() == ColumnName) 
            return true; 
    } //Still here? Column not found. 
    return false; 
}