以下应用程序代码在更新数据库记录时挂起。 它只在输出屏幕上显示0,并且程序永远挂起。 但是表中有超过50,000条记录。 (程序代码ISCII转换为Unicode并写入到数据库。)为什么我的应用程序在更新数据库记录时挂起?
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Collections;
using System.Data.SqlClient;
using System.Data.Sql;
namespace demoupdateform
{
public partial class Form1 : Form
{
System.IO.StreamWriter file = new System.IO.StreamWriter("c:\\test1.txt");
String[,] harltabcol = new String[,]
{
{"Col_name","Table_name"}
};
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
SqlConnection cn = new SqlConnection("Password=admin;Persist Security Info=True;User ID=sa;Initial Catalog=dbname;Data Source=DEEPAK-87E8B4");
SqlConnection cn1 = new SqlConnection("Password=admin;Persist Security Info=True;User ID=sa;Initial Catalog=dbname;Data Source=DEEPAK-87E8B4");
string temp;
string temp1;
try
{
for (int i = 0; i < harltabcol.GetLength(0); i++)
{
cn.Open();
SqlCommand cmdSel = new SqlCommand("select [" + harltabcol[i, 0] + "] from [" + harltabcol[i, 1] + "]",cn);
//cn.Open();
SqlDataReader rdr = cmdSel.ExecuteReader();
progressBar1.Value = 0;
int j = 0;
while (rdr.Read())
{
temp = (rdr[harltabcol[i, 0]].ToString()).ToString();
temp1 = (Iscii2Unicode(temp)).ToString();
SqlCommand cmdUpd = new SqlCommand("UPDATE [" + harltabcol[i,1] + "] SET [" + harltabcol[i,0] + "] =N'"+temp1+"' WHERE " + harltabcol[i,0] + "='" + temp + "'",cn1);
temp = rdr[harltabcol[i, 0]].ToString();
cn1.Open();
cmdUpd.CommandTimeout = 0;
Console.WriteLine(j++);
file.WriteLine(temp+" --> "+temp1);
progressBar1.Value = progressBar1.Value + 1;
if (progressBar1.Value == 99)
progressBar1.Value = 0;
cmdUpd.ExecuteNonQuery();
temp = null;
temp1 = null;
cn1.Close();
}
progressBar1.Value = 100;
cn.Close();
}
}
catch (Exception ex)
{
MessageBox.Show("Error Occured " + ex.ToString());
}
}
public string Iscii2Unicode(string IsciiStr)
{
Encoding EncFrom = Encoding.GetEncoding(1252);
Encoding EncTo = Encoding.GetEncoding(57002);
Byte[] b = EncFrom.GetBytes(IsciiStr);
return EncTo.GetString(b);
}
private void Form1_Load(object sender, EventArgs e)
{
}
}
}
关于[WinForms Threading](http://www.yoda.arachsys.com/csharp/threads/winforms.shtml)的一个很好的资源,特别是关于UI线程的部分。这应该有助于你理解它为什么会挂起,以及Serge为什么会修复它。 –