How to use SqlBulkCopyColumnMappingCollection?

Question

I want to make one SqlBulkCopy method that I can use for all my bulk inserts by passing in specific data through the parameters.

Now I need to do mapping on some of them. I don't know how to make a SqlBulkCopyColumnMappingCollection since that was my plan to pass in the mapping collection in and use it. However I don't know how to make it. I can't make a new object of it.

This is what I have now. How can I add it do mapping put pass it in?

public void BatchBulkCopy(DataTable dataTable, string DestinationTbl, int batchSize)
{
    // Get the DataTable 
    DataTable dtInsertRows = dataTable;

    using (SqlBulkCopy sbc = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.KeepIdentity))
    {
        sbc.DestinationTableName = DestinationTbl;

        // Number of records to be processed in one go
        sbc.BatchSize = batchSize;

        // Finally write to server
        sbc.WriteToServer(dtInsertRows);
    }
}

Answer 1

You don't need to create a new instance of it - the SqlBulkCopy class has a property which is a mapping collection that you can use:

public void BatchBulkCopy(DataTable dataTable, string DestinationTbl, int batchSize)
{
    // Get the DataTable 
    DataTable dtInsertRows = dataTable;

    using (SqlBulkCopy sbc = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.KeepIdentity))
    {
        sbc.DestinationTableName = DestinationTbl;

        // Number of records to be processed in one go
        sbc.BatchSize = batchSize;

        // Add your column mappings here
        sbc.ColumnMappings.Add("field1","field3");
        sbc.ColumnMappings.Add("foo","bar");

        // Finally write to server
        sbc.WriteToServer(dtInsertRows);
    }    
}

EDIT:

Based on the comments, the goal was to make a generic function, e.g. not have to hardcode the mapping explicitly in the function. Since the ColumnMappingCollection cannot be instantiated, I would recommend passing a List<string> or similar that contains the column mapping definition into the function. For example:

var columnMapping = new List<string>();
columnMapping.Add("field1,field3");
columnMapping.Add("foo,bar");

Then re-define the function as

public void BatchBulkCopy(DataTable dataTable, string DestinationTbl, int batchSize, List<string> columnMapping)
{
    // Get the DataTable 
    DataTable dtInsertRows = dataTable;

    using (SqlBulkCopy sbc = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.KeepIdentity))
    {
        sbc.DestinationTableName = DestinationTbl;

        // Number of records to be processed in one go
        sbc.BatchSize = batchSize;

        // Add your column mappings here
        foreach(var mapping in columnMapping)
        {
            var split = mapping.Split(new[] { ',' });
            sbc.ColumnMappings.Add(split.First(), split.Last());
        }

        // Finally write to server
        sbc.WriteToServer(dtInsertRows);
    }
}