Question

I want to validate if the field really exist in the table in the database. I have used the SqlDataReader class for the reading of data. After assigning the value to the SqlDataReader I made a loop to iterate each record using foreach. Here is the sample code.

SqlCommand sqlCommand = new SqlCommand();

SqlDataReader sqlDr = sqlCommand.ExecuteReader();

Foreach(DbDataRecord record in sqlDr)
{
    // Validate if the value is not null and (I want to validate if this field really exist in the table)
    if(record["MyField1"].GetType().ToString() == "System.DBNull")
    {
        // Statement here
    }
}

I hope for a kind answer. Thank you very much.

Answer 1

I would write an extension method which iterates thru each fields in the reader and return true/false.

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;
    }
}

Then call it like this

if (objReader.HasColumn("FirstName")
{
  //Column exist. So lets read the value
   someobject.Name= objReader.GetString(objReader.GetOrdinal("FirstName"));
}