使用FILESTREAM(文件流)写入数据
在这个例子中,假设用户产生了一些输入,要将这些输入内容转换成字节数组,并将其存储在Product表的Picture列中,接下来创建一个Visual C#视窗应用程序,命名为FileStreamExample,在新项目的默认表单上,添加一个按钮,命名为btnWriteFile,一个名叫txtInput的文本输入框(TextBox),一个命名为lstResults的列表框(ListBox),然后,在按钮上双击创建一个click事件处理器,包括清单1中的代码。
清单1 使用FILESTREAM存储数据
private void btnWriteFile_Click(object sender, EventArgs e)
{
string connectionString =
ConfigurationManager.ConnectionStrings
["fileStreamDB"].ConnectionString;
using (SqlConnection connection = new
SqlConnection(connectionString))
{
connection.Open();
SqlCommand command = new SqlCommand();
command.Connection = connection;
//Get the PathName of the File from the database
command.CommandText = "SELECT Picture.PathName(), " +
"GET_FILESTREAM_TRANSACTION_CONTEXT() FROM Product " +
"WHERE ProductID = 1";
SqlTransaction transaction = connection.BeginTransaction
(IsolationLevel.ReadCommitted);
command.Transaction = transaction;
using (SqlDataReader reader = command.ExecuteReader())
{
while (reader.Read())
{
string path = reader.GetString(0);
SqlFileStream stream = new SqlFileStream(path,
(byte[])reader.GetValue(1), FileAccess.Write,
FileOptions.SequentialScan, 0);
string contents = txtInput.Text;
stream.Write((System.Text.Encoding.ASCII.GetBytes(contents)),
0, contents.Length);
stream.Close();
}
}
transaction.Commit();
}
MessageBox.Show("File contents successfully written");
}
它从app.config使用ConfigurationManager.ConnectionStrings属性检索连接字符串:
string connectionString = ConfigurationManager.ConnectionStrings |


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