ComboBox上的SelectedIndexChanged方法的C＃問題

我正在學習C＃並且正在製作一個自定義的工資覈算應用程序。我有一份僱主期的表格，允許用戶一次輸入/編輯或刪除一個工資覈算期，即在給定時間只能有一個記錄在數據庫中。ComboBox上的SelectedIndexChanged方法的C＃問題

我有一個表單加載的方法，如果存在工資期限，它將檢索所有需要的字段。

代碼：

private void PayrollPeriodForm_Load(object sender, EventArgs e) 
{ 
    dateTimePicker2.Value = dateTimePicker2.Value.AddYears(1).AddDays(-1); 

    // Get service instance 
    var employerPeriodService = Program.Kernel.Get<IEmployerPeriodService>(); 

    //Query database 
    var employerPeriods = employerPeriodService.GetAllEmployerPeriods();          

    if (employerPeriods.Any(x => x != null)) 
    { 
     var employerPeriod = employerPeriods.First(); 

     txt_tax_year.Text = employerPeriod.U_Tax_year.ToString(); 
     lbl_code.Text = employerPeriod.Code; 
     cb_number_hours.Text = employerPeriod.U_Day_hrs.ToString(); 
     cb_number_days_week.Text = employerPeriod.U_Week_days.ToString(); 
     cb_number_days_month.Text = employerPeriod.U_Month_days.ToString(); 
     cb_number_days_fortnight.Text = employerPeriod.U_Fortnight_days.ToString(); 
     txt_number_hours_week.Text = employerPeriod.U_Week_hrs.ToString(); 
     txt_number_hours_fortnight.Text = employerPeriod.U_Fortnight_hrs.ToString(); 
     txt_number_hours_month.Text = employerPeriod.U_Month_hrs.ToString(); 
     cb_avg_weeks_month.Text = employerPeriod.U_Weeks_in_month.ToString(); 
     cb_avg_fortnights_month.Text = employerPeriod.U_No_of_Fortnights.ToString(); 
     dateTimePicker1.Text = employerPeriod.U_Starting_period.ToString(); 
     dateTimePicker2.Text = employerPeriod.U_Ending_period.ToString(); 

     txt_tax_year.Enabled = false; 
     dateTimePicker1.Enabled = false; 
     dateTimePicker2.Enabled = false; 
     btn_add.Enabled = false; 
     btn_update.Enabled = true; 
     btn_delete.Enabled = true; 
     btn_update.Visible = true; 
     btn_delete.Visible = true; 
     btn_add.Visible = false; 

     // Store SAP code 
     SAPCodePeriod = employerPeriod.Code; 
    } 
    else 
    { 
     //clear textfields after input 
     cb_number_hours.SelectedIndex = 0; 
     cb_number_days_week.SelectedIndex = 0; 
     txt_number_hours_week.Text = ""; 
     cb_number_days_month.SelectedIndex = 0; 
     txt_number_hours_month.Text = ""; 
     cb_number_days_fortnight.SelectedIndex = 0; 
     txt_number_hours_fortnight.Text = ""; 
     cb_avg_weeks_month.Text = null; 
     cb_avg_fortnights_month.Text = null; 
     lbl_code.Text = ""; 

     txt_tax_year.Enabled = true; 
     dateTimePicker1.Enabled = true; 
     dateTimePicker2.Enabled = true; 
     btn_add.Enabled = true; 
     btn_update.Enabled = false; 
     btn_delete.Enabled = false; 
     btn_add.Visible = true; 
     btn_update.Visible = false; 
     btn_delete.Visible = false; 
    } 
}

我有兩個selectd指數變化事件對我的組合框的2到目前爲止：

private void cb_number_hours_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    // calculate hours/week 
    var hoursWeek = (int.Parse(cb_number_hours.Text)) * (int.Parse(cb_number_days_week.Text)); 

    txt_number_hours_week.Text = hoursWeek.ToString(); 
} 

private void cb_number_days_week_SelectedIndexChanged(object sender, EventArgs e) 
{ 
    // calculate hours/week 
    var hoursWeek = (int.Parse(cb_number_hours.Text)) * int.Parse(cb_number_days_week.Text); 

    txt_number_hours_week.Text = hoursWeek.ToString(); 
}

我的問題：之前，我有任何的SelectedIndexChanged方法，所有的數據庫中的值顯示在適當的文本框和組合框中。

但是，在添加cb_number_hours_SelectedIndexChanged方法後，停止顯示後，來自DB的所有文本框和組合框值。這導致方法中的計算不起作用(int.Parse(cb_number_days_week.Text))被視爲空。

我該如何解決這個問題？

來源

2011-07-11 Kinyanjui Kamau

這不回答你的問題，但以下是沒有意義的：var employerPeriods =從EP中employerPeriodService 。GetAllEmployerPeriods（） select ep; 您可以編寫var employerPeriods = employerPeriodService.GetAllEmployerPeriods（）;而不是 – Dismissile

true;從中選擇，忘記刪除不必要的 –

在你cb_number_hours_SelectedIndexChanged事件處理程序，嘗試adding a check for a valid value你的代碼的其餘部分之前，像這樣（未經）：

int hours; 
int days; 

if (Int32.TryParse(cb_number_hours.Text, out hours) && Int32.TryParse(cb_number_days_week.Text, out days)) 
{ 
    var hoursWeek = hours * days; 
    txt_number_hours_week.Text = hoursWeek.ToString(); 
}

來源

2011-07-11 13:32:28 BrandonZeider

感謝您的回覆。 –

ComboBox上的SelectedIndexChanged方法的C＃問題

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