它插入多个数据而不是一个

Question

我正在使用SQL Server 2014，我的问题是，当我单击“保存”按钮以保存Salary数据时，它提供了多个数据而不是一个数据，这是我的代码：

   private void btnStart_Click(object sender, EventArgs e)
    {
        con.dataGet("Select * from EmpAttendance Where Year = '" + 
  cmbYear.Text + "' and Month = '" + cmbMonth.Text + "'");
        DataTable dt = new DataTable();
        con.sda.Fill(dt);


        if(dt.Rows.Count > 0)
        {
            foreach(DataRow row in dt.Rows)
            {
                con.dataGet(@"SELECT ES.Salary, EA.WorkingDays,                  
     EA.Presentdays, EA.LopDays FROM EmpAttendance EA INNER JOIN 
     EmpSalary ES ON EA.EmpId = ES.EmpId
                        Where EA.Year = '"+ cmbYear.Text +"' and EA.Month 
     = '"+ cmbMonth.Text +"' and EA.EmpId = '"+ dt.Rows[0] 
     ["EmpId"].ToString() +"'");


                DataTable dt1 = new DataTable();
                con.sda.Fill(dt1);


                salary = float.Parse(dt1.Rows[0]["Salary"].ToString());
                workingDays = float.Parse(dt1.Rows[0]["WorkingDays"].ToString());
                present = float.Parse(dt1.Rows[0]["PresentDays"].ToString());
                lop = float.Parse(dt1.Rows[0]["LopDays"].ToString());
                perDay = (salary / 12) / workingDays;
                netSalary = (perDay * present) - (perDay * lop);


                con.dataSend("INSERT INTO SalaryProcess (EmpId, Year, 
      Month, NetSalary) VALUES ('" + dt.Rows[0]["EmpId"].ToString() + "', 
      '" + cmbYear.Text + "', '" + cmbMonth.Text + "', '" + netSalary + 
      "')");


                MessageBox.Show("Salary Generated!", "Message", 
      MessageBoxButtons.OK, MessageBoxIcon.Information);
                LoadData();
            }
        }
    }