如何使用ASP.Net SqlBulkCopy将常量值插入到列中

DataTable dataTable = new DataTable();
dataTable.Columns.Add("Column1");
dataTable.Columns.Add("Column2");
dataTable.Columns.Add("Column3");

DataRow dataRow = dataTable.NewRow();
dataRow["Column1"] = "Value1";
dataRow["Column2"] = "Value2";
dataRow["Column3"] = "Value3";
dataTable.Rows.Add(dataRow);

using (SqlConnection connection = new SqlConnection(connectionString))
{
    using (SqlBulkCopy bulkCopy = new SqlBulkCopy(connection))
    {
        bulkCopy.DestinationTableName = "TableName";
        bulkCopy.ColumnMappings.Add("Column1", "Column1");
        bulkCopy.ColumnMappings.Add("Column2", "Column2");
        bulkCopy.ColumnMappings.Add("Column3", "Column3");
        connection.Open();
        bulkCopy.WriteToServer(dataTable);
    }
}

DataRow dataRow = dataTable.NewRow();
dataRow["Column1"] = "Value1";
dataRow["Column2"] = "Value2";
dataRow["Column3"] = "Value3";
dataRow["Column4"] = "ConstantValue";
dataTable.Rows.Add(dataRow);