錯誤連接到SQL，asp.net C＃

Question

我與編寫JavaScript代碼倒計時：

<script language="JavaScript"> 
TargetDate = "<% = TargetDate %>"; 
/*this is a property in code behind*/BackColor = "palegreen"; 
ForeColor = "navy"; 
CountActive = true; 
CountStepper = -1; 
LeadingZero = true; 
DisplayFormat = "%%D%% Days, %%H%% Hours, %%M%% Minutes, %%S%% Seconds."; 
FinishMessage = "the auction end" 
</script> 
<script language="JavaScript" src="countdown.js"></script> 
</script> 

後面的代碼：

public string TargetDate() 
{ 

    DataTable dataTable = new DataTable(); 
    using (SqlConnection connection = new SqlConnection("Server=localhost;Database=Timer;Trusted_Connectopn=True")) 
    using (SqlCommand command = connection.CreateCommand()) 
    { 
     command.CommandText = "select * from endTime"; 
     connection.Open(); 
     SqlDataReader reader = command.ExecuteReader(); 
     dataTable.Load(reader); } 
} 

我得到的錯誤： 「T .TargetDate（）'：不是所有的代碼路徑都返回值。

當我試着寫了回報，我得到了另一個錯誤...什麼意思，我不知道該怎麼做:)

Answer 1

你應該返回字符串的方法。它沒有。

public string TargetDate

沒有return。

使用ExecuteScalar而不是ExecuteReader。

返回字符串值。

Answer 2

你也有拼寫錯誤您的連接字符串中：Trusted_Connectopn應該是所有的Trusted_Connection

Answer 3

首先，你必須根據你的功能規格爲字符串返回targetdate值。 您應該閱讀數據表並返回。像這樣的東西

public string TargetDate() 
{ 
    String tDate = ""; 
    DataTable dataTable = new DataTable(); 
    using (SqlConnection connection = new SqlConnection("Server=localhost;Database=Timer;Trusted_Connection=True")) 
    using (SqlCommand command = connection.CreateCommand()) 
    { 
     command.CommandText = "select * from endTime"; 
     connection.Open(); 
     SqlDataReader reader = command.ExecuteReader(); 
     dataTable.Load(reader); 
     tDate = dataTable.Rows[0][0].toString(); // Expecting the first row and first column 
} 
return tDate; 
} 

希望這會有所幫助。