dataSet.GetXml() doesn't return xml for null or blank columns

Question

When I call dataSet.GetXml() I don\'t get any xml returned for columns with null or blank values. Is there a simple, efficient way to get around this? An example of the prob

Answer 1

I have been searching the whole world for a solution of writing null fields to XML using DataSet.WriteXML(). I found that following works in a performance optimized way. I have created a function for your convenience. Change your dataset tables one after the other by calling the following function and replacing the tables.

    private DataTable GetNullFilledDataTableForXML(DataTable dtSource)
    {
        // Create a target table with same structure as source and fields as strings
        // We can change the column datatype as long as there is no data loaded
        DataTable dtTarget = dtSource.Clone();
        foreach (DataColumn col in dtTarget.Columns)
            col.DataType = typeof(string);

        // Start importing the source into target by ItemArray copying which 
        // is found to be reasonably fast for nulk operations. VS 2015 is reporting
        // 500-525 milliseconds for loading 100,000 records x 10 columns 
        // after null conversion in every cell which may be usable in many
        // circumstances.
        // Machine config: i5 2nd Gen, 8 GB RAM, Windows 7 64bit, VS 2015 Update 1
        int colCountInTarget = dtTarget.Columns.Count;
        foreach (DataRow sourceRow in dtSource.Rows)
        {
            // Get a new row loaded with data from source row
            DataRow targetRow = dtTarget.NewRow();
            targetRow.ItemArray = sourceRow.ItemArray;

            // Update DBNull.Values to empty string in the new (target) row
            // We can safely assign empty string since the target table columns
            // are all of string type
            for (int ctr = 0; ctr < colCountInTarget; ctr++)
                if (targetRow[ctr] == DBNull.Value)
                    targetRow[ctr] = String.Empty;

            // Now add the null filled row to target datatable
            dtTarget.Rows.Add(targetRow);
        }

        // Return the target datatable
        return dtTarget;
    }