每次按下按钮都会更新数据库

Question

下面是记分牌应用程序的代码，我试图在其中维护智力竞赛节目的团队分数。该应用程序的工作原理是，如果您想给 A 队打分，请先按 A 键，然后按按钮 1、2、3、4、5 或 6 打分（+5、+10、+15、-5、 -10 或 -15）。我想为标记创建一个数据库并在每次按下按钮时更新它们。

Label target = new Label();
int vA = 0;

private void frmScoreBoard_KeyUp(object sender, KeyEventArgs e) {
   if (e.KeyCode == Keys.A) {
      target = lblScoreA;
   }

   if (e.KeyCode == Keys.B) {
      target = lblScoreB;
   }

   if (e.KeyCode == Keys.C) {
      target = lblScoreC;
   }

   if (target.Text != "") {
      if (e.KeyCode == Keys.D1 || e.KeyCode == Keys.NumPad1) {
         vA = int.Parse(target.Text);
         vA += 5;

         target.Text = vA.ToString();
      }
      if (e.KeyCode == Keys.D2 || e.KeyCode == Keys.NumPad2) {
         vA = int.Parse(target.Text);
         vA += 10;
         target.Text = vA.ToString();
      }
      if (e.KeyCode == Keys.D3 || e.KeyCode == Keys.NumPad3) {
         vA = int.Parse(target.Text);
         vA += 15;
         target.Text = vA.ToString();
      }
      if (e.KeyCode == Keys.D4 || e.KeyCode == Keys.NumPad4) {
         vA = int.Parse(target.Text);
         vA -= 5;
         target.Text = vA.ToString();
      }
      if (e.KeyCode == Keys.D5 || e.KeyCode == Keys.NumPad5) {
         vA = int.Parse(target.Text);
         vA -= 10;
         target.Text = vA.ToString();
      }
      if (e.KeyCode == Keys.D6 || e.KeyCode == Keys.NumPad6) {
         vA = int.Parse(target.Text);
         vA -= 15;
         target.Text = vA.ToString();
      }
   }
}

我知道 ADO.NET 和连接，但我不知道每次如何更新。我不需要代码 - 我只是想知道如何去做。

ADO.NET 代码：

using (SqlConnection con = new SqlConnection(CS)) {
   SqlCommand cmd = new SqlCommand("update tblScore set Score='" + Convert.ToInt32(lblScoreA.Text) + "'where TeamName= '" + Convert.ToInt32(lblTeamA.Text) + "'", con);
   SqlCommand cmd1 = new SqlCommand("update tblScore set Score='" + Convert.ToInt32(lblScoreB.Text) + "'where TeamName= '" + Convert.ToInt32(lblTeamB.Text) + "'", con);
   cmd1.ExecuteNonQuery();
   SqlCommand cmd2 = new SqlCommand("update tblScore set Score='" + Convert.ToInt32(lblScoreC.Text) + "'where TeamName= '" + Convert.ToInt32(lblTeamC.Text) + "'", con);
   cmd2.ExecuteNonQuery();
}

有人能帮忙吗？

Answer 1

您可以创建一个单独的方法来更新带有分数的团队：

private void UpdateTeamScore(string teamName, int score) {

   using (SqlConnection con = new SqlConnection(CS)) {
      con.Open();

      using (SqlCommand command = new SqlCommand("UPDATE tblScore SET Score = @Score WHERE TeamName = @TeamName;", con)) {
         command.Parameters.Add(new SqlParameter("Score", score));
         command.Parameters.Add(new SqlParameter("TeamName", teamName));
         command.ExecuteNonQuery();
      }
   }
}

并分离您的 KeyUp 逻辑：

private String activeTeam = null;
private void frmScoreBoard_KeyUp(object sender, KeyEventArgs e) {

   // If the user used team selection keys
   if ((e.KeyCode == Keys.A) || (e.KeyCode == Keys.B) || (e.KeyCode == Keys.C)) {

      // Select the team according to pressed key
      ActivateTeamForScoring(e);

      // Return as we don't need to do anything else on this keystroke
      return;
   }

   // If the user came here by pressing the scoring keys
   else {

      // If a team wasn't set, return
      if (activeTeam == null) { return; }

      // Resolve the score according to pressed key
      int? score = ResolveScore(e);

      // If the user pressed correct score key, update
      if (score != null) {

         // Perform the score update to database
         UpdateTeamScore(activeTeam, score.Value);
      }

      // Reset active team after scoring
      activeTeam = null;
   }
}

private void ActivateTeamForScoring(KeyEventArgs e) {

   // Set the right team to be scored
   if (e.KeyCode == Keys.A) {
      activeTeam = lblScoreA;
   } else if (e.KeyCode == Keys.B) {
      activeTeam = lblScoreB;
   } else if (e.KeyCode == Keys.C) {
      activeTeam = lblScoreC;
   }
}

private int? ResolveScore(KeyEventArgs e) {

  if (e.KeyCode == Keys.D1 || e.KeyCode == Keys.NumPad1) {
     return 5;
  } else if (e.KeyCode == Keys.D2 || e.KeyCode == Keys.NumPad2) {
     return 10;
  } else if (e.KeyCode == Keys.D3 || e.KeyCode == Keys.NumPad3) {
     return 15;
  } else if (e.KeyCode == Keys.D4 || e.KeyCode == Keys.NumPad4) {
     return -5;
  } else if (e.KeyCode == Keys.D5 || e.KeyCode == Keys.NumPad5) {
     return -10;
  } else if (e.KeyCode == Keys.D6 || e.KeyCode == Keys.NumPad6) {
     return -15;

  // If the keystroke was invalid, return null
  } else {
     return null;
  }
}

Answer 2

原则有效...您需要先打开连接，然后再对其执行运行命令，因此请使用

con.Open();

您可以将所有更新放在一个命令中。另外，文本框中的数据是字符串，因此您无需先将其转换为 int。

using (SqlConnection con = new SqlConnection(CS)) {
    con.Open();
    // Create one string with all the updates in it... 
    string query = string.Format("UPDATE tblScore SET Score={0} WHERE TeamName='{1}'; ", lblScoreA.Text, lblTeamA.Text);
    query += string.Format("UPDATE tblScore SET Score={0} WHERE TeamName='{1}'; ", lblScoreB.Text, lblTeamB.Text);
    query += string.Format("UPDATE tblScore SET Score={0} WHERE TeamName='{1}'; ", lblScoreC.Text, lblTeamC.Text);

    SqlCommand cmd = new SqlCommand(query, con);
    cmd.ExecuteNonQuery();
    }

每次按下按钮都会更新数据库

Database update on each button press

c#

sql-server

ado.net