交易過程 - 死鎖錯誤

Question

當我從軟件更新數據時，我正面臨着死鎖錯誤。

這裏是我的代碼：

所有的

private void btn_upd_Click(object sender, EventArgs e) 
{ 
    try 
    { 
     SqlConnection con = new SqlConnection(Constr); 
     con.Open(); 
     string myquery = "Select Reg,Rank,Trade,Name,Wing,Father_name,Dob,Gender,Cast,Sect,Serial,Qualification,Tehseel,District,Cnic_No,Blood_Group,Height,Weight,Identification_Mark,Permanent_Add,Nameof_Spouse,Relation,Nameof_MaleKids,image1 from PersonalInfo where Reg='" + txt_srch.Text + "'"; 

     SqlCommand c = new SqlCommand(myquery, con); 

     SqlDataReader rd = c.ExecuteReader(); 

     if (!(rd.HasRows)) 
     { 
      MessageBox.Show("No such data to delete"); 
     } 
     else 
     { 
      string query; 

      query = "update PersonalInfo set Rank='" + textBox2.Text + "', Serial='" + SN.Text + "', Trade='" + textBox3.Text + "',Name='" + textBox4.Text + "',Wing='" + textBox5.Text + "',Father_name='" + textBox6.Text + "',Dob='" + textBox7.Text + "',Gender='" + textBox8.Text + "',Cast='" + textBox9.Text + "',Sect='" + textBox23.Text + "',Qualification='" + textBox10.Text + "',Tehseel='" + textBox24.Text + "',District='" + textBox21.Text + "',Cnic_No='" + textBox11.Text + "',Blood_Group='" + textBox12.Text + "',Height='" + textBox13.Text + "',Weight='" + textBox14.Text + "',Identification_Mark='" + textBox15.Text + "',Permanent_Add='" + textBox16.Text + "',Nameof_Spouse='" + textBox18.Text + "',Relation='" + textBox19.Text + "',Nameof_MaleKids='" + textBox20.Text + "',image1='" + ImageToBase64(pictureBox1.Image, System.Drawing.Imaging.ImageFormat.Jpeg) + "' where Reg='" + txt_srch.Text + "'"; 

      SqlCommand cmd = new SqlCommand(query, con); 
      cmd.ExecuteNonQuery(); 
      MessageBox.Show("Data Updated"); 
     } 
     con.Close(); 
    } 
    catch (Exception ex) 
    { 
     MessageBox.Show(ex.Message); 
    } 
} 

Answer 1

首先，marc_s已經說過，從用戶直接輸入串聯您的疑問是危險的。建議您應該考慮更改該方法並使用參數化查詢。

其次，嘗試自己的連接Open()和Close()內運行的每個查詢：

private void btn_upd_Click(object sender, EventArgs e) 
{ 
    try 
    { 
     SqlConnection con = new SqlConnection(Constr); 

     con.Open(); 

     string myquery = "Select Reg,Rank,Trade,Name,Wing,Father_name,Dob,Gender,Cast,Sect,Serial,Qualification,Tehseel,District,Cnic_No,Blood_Group,Height,Weight,Identification_Mark,Permanent_Add,Nameof_Spouse,Relation,Nameof_MaleKids,image1 from PersonalInfo where Reg='" + txt_srch.Text + "'"; 

     SqlCommand c = new SqlCommand(myquery, con); 

     SqlDataReader rd = c.ExecuteReader(); 

     con.Close(); 

     if (!(rd.HasRows)) 
     { 
      MessageBox.Show("No such data to delete"); 
     } 
     else 
     { 
      con.Open(); 

      string query; 

      query = "update PersonalInfo set Rank='" + textBox2.Text + "', Serial='" + SN.Text + "', Trade='" + textBox3.Text + "',Name='" + textBox4.Text + "',Wing='" + textBox5.Text + "',Father_name='" + textBox6.Text + "',Dob='" + textBox7.Text + "',Gender='" + textBox8.Text + "',Cast='" + textBox9.Text + "',Sect='" + textBox23.Text + "',Qualification='" + textBox10.Text + "',Tehseel='" + textBox24.Text + "',District='" + textBox21.Text + "',Cnic_No='" + textBox11.Text + "',Blood_Group='" + textBox12.Text + "',Height='" + textBox13.Text + "',Weight='" + textBox14.Text + "',Identification_Mark='" + textBox15.Text + "',Permanent_Add='" + textBox16.Text + "',Nameof_Spouse='" + textBox18.Text + "',Relation='" + textBox19.Text + "',Nameof_MaleKids='" + textBox20.Text + "',image1='" + ImageToBase64(pictureBox1.Image, System.Drawing.Imaging.ImageFormat.Jpeg) + "' where Reg='" + txt_srch.Text + "'"; 

      SqlCommand cmd = new SqlCommand(query, con); 

      cmd.ExecuteNonQuery(); 

      con.Close(); 

      MessageBox.Show("Data Updated"); 
     } 
    } 
    catch (Exception ex) 
    { 
     MessageBox.Show(ex.Message); 
    } 
}