/// <summary>
/// 
/// </summary>
/// <param name="connectionString">目标连接字符</param>
/// <param name="TableName">目标表</param>
/// <param name="dt">源数据</param>
private void SqlBulkCopyByDatatable(string connectionString, string TableName, DataTable dt)
{
    using (SqlConnection conn = new SqlConnection(connectionString))
    {
        using (SqlBulkCopy sqlbulkcopy = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.UseInternalTransaction))
        {
            try
            {
                sqlbulkcopy.DestinationTableName = TableName;
                sqlbulkcopy.ColumnMappings.Add("test2", "test2"); //两个参数第一个是数据库的名称、第二个是DataTable的列名
                sqlbulkcopy.WriteToServer(dt);
            }
            catch (System.Exception ex)
            {
                throw ex;
            }
        }
    }
}

 DataTable dt = new DataTable();
            dt.Columns.Add("test2", System.Type.GetType("System.String"));
            //添加行数据
            for (int i = 0; i < 100; i++)
            {
                DataRow dr = dt.NewRow();
                dr["test2"] = "test2";
                dt.Rows.Add(dr);
            }
qlBulkCopyByDatatable(sqlcon, "tableName", dt);