错误连接到SQL，asp.net C＃

Question

我与编写JavaScript代码倒计时：

<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> 

后面的代码：

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); } 
} 

我得到的错误： “T .TargetDate（）'：不是所有的代码路径都返回值。

当我试着写了回报，我得到了另一个错误...什么意思，我不知道该怎么做:)

Answer 1

你应该返回字符串的方法。它没有。

public string TargetDate

没有return。

使用ExecuteScalar而不是ExecuteReader。

返回字符串值。

Answer 2

你也有拼写错误您的连接字符串中：Trusted_Connectopn应该是所有的Trusted_Connection

Answer 3

首先，你必须根据你的功能规格为字符串返回targetdate值。 您应该阅读数据表并返回。像这样的东西

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; 
} 

希望这会有所帮助。