日期檢查器的IF語句ASP.NET

Question

我在爲一個賦值工作掙扎，試圖讓我的代碼檢查結束日期必須比C＃中ASP.NET中的開始日期更晚。老師說：

Create an If statement to check that both start and end date exist as COMPOUND condition. Hint: use &&. Inside this if statement (check date-difference)

這是我有：

DateTime startDate = DateTime.Parse(Request["txtStartDate"]); 
    DateTime endDate = DateTime.Parse(Request["txtEndDate"]); 
    if (DateTime.Compare(startDate, endDate) > 0) 
    { 
     txtStartDate.BackColor = System.Drawing.Color.Yellow; 
     txtEndDate.BackColor = System.Drawing.Color.Yellow; 
     lblError.Text += "The end date must be a later date than the start date."; 
     //The Msg text will be displayed in lblError.Text after all the error messages are concatenated 
     bIsFormValid = false; 
     //Boolean value - test each textbox to see if the data entered is valid, if not set validState=false. 
     //If after testing each validation rule, the validatedState value is true, then submit to frmPersonnelVerified.aspx, if not, then display error message 
    } 
    else 
    { 
     txtStartDate.BackColor = System.Drawing.Color.White; 
     txtEndDate.BackColor = System.Drawing.Color.White; 
    } 


    // Redirect the User to frmStudentConfirmed.aspx 
    if (bIsFormValid) 
    { 
     Response.Redirect("frmPersonnelVerified.aspx"); 
    } 
    else 
    { 
     Session.Clear(); 
    } 

我收到以下錯誤：

An exception of type 'System.FormatException' occurred in mscorlib.dll but was not handled in user code. Additional information: String was not recognized as a valid DateTime. 

任何幫助將不勝感激。 米格爾

Answer 1

好像問題是與您試圖在

Request["txtStartDate"] 

或

Request["txtEndDate"] 

DateTime.Prase靜態方法來通過默認接受的格式數量的日期格式檢查 https://www.dotnetperls.com/datetime-parse

如果由於某種原因需要以其他格式傳遞日期，請嘗試使用

DateTime.ParseExact https://msdn.microsoft.com/en-us/library/w2sa9yss(v=vs.110).aspx