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Showing posts from December, 2007

How to Determine if a Column Exists in a DataReader

I recently had to work on something which required me to query a database, open the results in a DataReader, and check for the existence of a particular column. While the DataReader doesn't have a method to do this, with just a few steps I was able to accomplish this task. Here's how.

First, the DataReader has a method named GetSchemaTable(), which returns a DataTable consisting of information regarding the data contained in the DataReader. The first column in this DataTable is named ColumnName, and its value is (obviously) the name of the column.

Knowing this, we can loop through the rows in the DataTable, checking the ColumnName column for a value that equals the name of the column we're looking for. To this end, I wrote a static method in one of my classes which takes the DataReader and the name of the column being sought:


(C#)
public static bool HasColumn(DbDataReader Reader, string ColumnName)
{
   foreach (DataRow row in Reader.GetSchemaTable().Rows)
   {
      if (row[&…