并非所有的代码路径都返回值???

Question

我写了一个新闻读取的类，但是出现标题所出的问题。
这是我的详细代码：
前台：
<table border="1">
<tr><td style="width: 293px" runat="server" id="tt1">&nbsp;</td></tr>
</table>
后台
 protected void Page_Load(object sender, EventArgs e)
    {
        string str = "select top 5 * from news where type_ids=51 order by id desc";
        access.yj(str,tt1);
    }调用的类：
public static string yj(string str,HtmlTableCell tt)
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["GirlsysConnectionString"].ConnectionString);//连接数据库
        try
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand(str, conn);
            SqlDataReader dea = cmd.ExecuteReader();
            while (dea.Read())
            { 
                tt.InnerText +="<a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>" + access.Substr(dea["title"].ToString(), 0, 11);
                return tt.InnerText;
            }
        }
        catch
        {
            return tt.InnerText;
        }
        finally
        {
            conn.Close();
        }
    }
谢谢各位了
    

Answer 1

while (dea.Read())
            {
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>" + access.Substr(dea["title"].ToString(), 0, 11);
                return tt.InnerText;
            } 如果while 里面没有执行，又没有出异常，就出问题了！

Answer 2

这一句的位置不对！
return tt.InnerText; 

Answer 3

public static string yj(string str,HtmlTableCell tt) 
    { 
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["GirlsysConnectionString"].ConnectionString);//连接数据库 
        try 
        { 
            conn.Open(); 
            SqlCommand cmd = new SqlCommand(str, conn); 
            SqlDataReader dea = cmd.ExecuteReader(); 
            while (dea.Read()) 
            { 
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>" + access.Substr(dea["title"].ToString(), 0, 11); 
                return tt.InnerText; 
            } 
        } 
        catch 
        { 
            return tt.InnerText; 
        } 
        finally 
        { 
            conn.Close(); 
        } 
    } 你最后再返回 return "";可以了，
一般你可以在最外面声明个变量把数据赋给这个变量，最后只返回这个变量就可以了。

Answer 4

public static string yj(string str,HtmlTableCell tt)
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["GirlsysConnectionString"].ConnectionString);// 连接数据库
        try
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand(str, conn);
            SqlDataReader dea = cmd.ExecuteReader();
            while (dea.Read())
            {
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>" + access.Substr(dea["title"].ToString(), 0, 11);
                
            }
            return tt.InnerText;
        }
        catch
        {
            return tt.InnerText;
        }
        finally
        {
            conn.Close();
        }
    } 

Answer 5

改:public static string yj(string str,HtmlTableCell tt) 
    { 
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["GirlsysConnectionString"].ConnectionString);//连接数据库 
        try 
        { 
            conn.Open(); 
            SqlCommand cmd = new SqlCommand(str, conn); 
            SqlDataReader dea = cmd.ExecuteReader(); 
            while (dea.Read()) 
            { 
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>" + access.Substr(dea["title"].ToString(), 0, 11); 
                           } 
        } 
        catch 
        { 
            //return tt.InnerText; 
        } 
        finally 
        { 
            conn.Close(); 
        } 
 return tt.InnerText;     }

Answer 6

你的代码写错了:
   while (dea.Read()) 
            { 
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>"   +access.Substr(dea["title"].ToString(), 0, 11); 
                return tt.InnerText; 
            } 
应该是这样的吧:
   while (dea.Read()) 
            { 
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>"   +access.Substr(dea["title"].ToString(), 0, 11); 
            }
   return tt.InnerText; 

Answer 7

public static string yj(string str,HtmlTableCell tt)
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["GirlsysConnectionString"].ConnectionString);// 连接数据库
        try
        {
            conn.Open();
            SqlCommand cmd = new SqlCommand(str, conn);
            SqlDataReader dea = cmd.ExecuteReader();
            while (dea.Read())
            {
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>" + access.Substr(dea["title"].ToString(), 0, 11);
                return tt.InnerText;
            }
return string.empty;
        }
        catch
        {
            return tt.InnerText;
        }
        finally
        {
            conn.Close();
        }
    } 

Answer 8

while (dea.Read()) 
            { 
                tt.InnerText +=" <a href=\"news_look.aspx?id=" + dea["id"] + "\" target=_blank>" + access.Substr(dea["title"].ToString(), 0, 11); 
                return tt.InnerText; 
            }
你这个while 中的return造成了这个错误，所以在编译的时候报这个错误。6楼正解。
哎来晚了!!