關于.net(C#)中的跨進程訪問的問題
2024-07-10 13:20:23
供稿：網友
namespace process_image
{
public partial class jszg_upload : Form
{
static bool stop_flag = false;
public jszg_upload()
{
InitializeComponent();
}
private void upload_button1_Click(object sender, EventArgs e)
{
stop_flag = false;
if (this.checkBox1.Checked)
{
String connectionString = "連接串";
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
SqlCommand cmd = new SqlCommand(" update my_jszg set filemime=null, filebody = null", conn);
cmd.ExecuteNonQuery();
conn.Close();
}
}
new Thread(uploadImageToDB).Start();
}//end upload_button1_Click
void uploadImageToDB()
{
//第一步：發現文件夾下面的文件及數量
DirectoryInfo myFolder = new DirectoryInfo("bcd");
FileInfo[] myFiles = myFolder.GetFiles();
this.richTextBox1.Text = "從文件夾中發現了：" + myFiles.Length.ToString() + " 個文件！" + "/n";
this.jindutiao_progressBar1.Maximum = myFiles.Length;
//第二步：開始上傳文件
String connectionString = "連接串";
using (SqlConnection conn = new SqlConnection(connectionString))
{
conn.Open();
for (int i = 0; i < myFiles.Length; i++)
{
if(stop_flag)
break;
//進度條
this.jindutiao_progressBar1.Value = i + 1;
this.pictureBox1.ImageLocation = myFiles[i].FullName;
this.richTextBox1.Text = myFiles[i].Name + "/n" + this.richTextBox1.Text;
this.baifenbi_label1.Text = ((((i + 1) * 1.0) /myFiles.Length) * 100) + "%";
//上傳實際的數據image/jpeg
SqlCommand cmd = new SqlCommand(" update my_jszg set filemime='image/jpeg', filebody = @myfilebody from my_jszg where 證件號碼=@myzjhm", conn);
byte[] fb = new byte[myFiles[i].Length];
BinaryReader br = new BinaryReader(myFiles[i].OpenRead());
br.Read(fb, 0, (int)myFiles[i].Length);
cmd.Parameters.AddWithValue("@myfilebody", fb);
cmd.Parameters.AddWithValue("@myzjhm", myFiles[i].Name.Substring(0, myFiles[i].Name.LastIndexOf('.')));
cmd.ExecuteNonQuery();
br.Close();
}//end for
conn.Close();
}
MessageBox.Show("所有的文件上傳完畢！");
}
//停止上傳
private void stop_button_Click(object sender, EventArgs e)
{
stop_flag=true;
}
}
}
在此代碼中，對一個控件的訪問如： this.richTextBox1.Text = myFiles[i].Name + "/n" + this.richTextBox1.Text; 僅限在一個線程中，如果在兩個進程中對控件訪問將會出錯！如不能在程序自己的線程 和 uploadImageToDB 線程中訪問。
