使用 backgroundWorker 出现的异常问题

Question

错误信息如下 ：在 System.Data.SqlClient.SqlException 中第一次偶然出现的“System.Data.dll”类型的异常
高分求解办法  

Answer 1

private bool isSuccess;
 private void button2_Click(object sender, EventArgs e)
        {
            string ConnectionString = "server=" + txtServerIP.Text + ";database=" + txtdbname.Text + ";uid=" + txtuid.Text + ";pwd=" + txtpwd.Text + ";";
            backgroundWorker1.RunWorkerAsync(ConnectionString);
            button2.Enabled = false;
        }
//异步测试数据库连接
        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            if (DBManager.testconn(e.Argument.ToString()))
            {                isSuccess = true;
            }
            else
            {                isSuccess = false;
            }
        }
        //异步测试退出
        private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            if (backgroundWorker1.CancellationPending == false)
            {
                if (isSuccess)
                {
                    MessageBox.Show("测试成功，当前服务器可用", "提示信息");
                }
                else
                {
                    MessageBox.Show("测试失败，请检查服务器设置", "提示信息");
                }
                button2.Enabled = true;            }
        }
//取消
        private void button1_Click(object sender, EventArgs e)
        {
            backgroundWorker1.CancelAsync();
            this.button2.Enabled = true;
                    }

Answer 2

1.链接数据库的代码没有看到
2.WorkerSupportsCancellation是否为true？建议直接用BackgroundWorker bg_ConnectionSql=new BackgroundWorker();的方式来建立线程

Answer 3

WorkerSupportsCancellation=true;  已在界面属性中设置  操作数据库方法
        public static bool testconn(string connstr)
        {
            SqlConnection mySqlConnection; 
            string ConnectionString = connstr;
            mySqlConnection = new SqlConnection(ConnectionString);
            try
            {
                mySqlConnection.Open();
                return true;
            }
            catch
            {
                return false;
            }
            finally
            {
                mySqlConnection.Close();
            }
 
        }

Answer 4

操作数据库方法 
        public static bool testconn(string connstr) 
        { 
            SqlConnection mySqlConnection; 
            string ConnectionString = connstr; 
            mySqlConnection = new SqlConnection(ConnectionString); 
            try 
            { 
                mySqlConnection.Open(); 
                return true; 
            } 
            catch 
            { 
                return false; 
            } 
            finally 
            { 
                mySqlConnection.Close(); 
            }         }

Answer 5

1.看看异常的具体信息?可把异常tostring打印出来
2.我怀疑是数据库连接失败，mySqlConnection.Close()这句位置不对导致出错，应该放在mySqlConnection.Open(); 这句后面

Answer 6

不是数据库问题   那连接数据库方法注释了  也一样出错private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            if ((e.Argument.ToString())!="")
            {                isSuccess = true;
            }
            else
            {                isSuccess = false;
            }
        }