Question

我遇到此错误的问题：

C＃错误：“填充：SelectCommand.Connection属性尚未出现初始化“。

我喜欢其他线程，但人们认为它建立的客户差别不大，但它没有帮助。我不知道，为什么会出现这个错误。我想在SelectOsoba的某个地方出错了。我需要在DataGridView中显示数据。

我的代码是：

class Vrstva
{
    public static SqlConnection myConnection;
    public static string connstr;
    static DataTable t;

    public static void createConnect1()
    {
        connstr = ConfigurationSettings.AppSettings["local1"];
        Vrstva.myConnection = new SqlConnection(connstr);
    }
    public static void createConnect2()
    {
        connstr = ConfigurationSettings.AppSettings["local2"];
        Vrstva.myConnection = new SqlConnection(connstr);
    }
    public static void createConnect3()
    {
        connstr = ConfigurationSettings.AppSettings["local3"];
        Vrstva.myConnection = new SqlConnection(connstr);
    }
    public static void openConn()
    {
        Vrstva.myConnection.Open();
    }
    public static void closeConn()
    {
        Vrstva.myConnection.Close();
    }
    public static SqlDataAdapter Query(string command)
    {
        return new SqlDataAdapter(command, Vrstva.myConnection);
    }
    public static void NonQuery(string command)
    {
        SqlCommand Command = new SqlCommand(command, Vrstva.myConnection);
        Command.ExecuteNonQuery();
    }
    public static bool login1(string login, string password)
    {
        string login1 = ConfigurationSettings.AppSettings["login1"];
        string password1 = ConfigurationSettings.AppSettings["password1"];
        if (login == login1 && password == password1)
        {
            return true;
        }
        return false;

    }
    public static bool login2(string login, string password)
    {
        string login1 = ConfigurationSettings.AppSettings["login2"];
        string password1 = ConfigurationSettings.AppSettings["password2"];
        if (login == login1 && password == password1)
        {
            return true;
        }
        return false;

    }
    public static bool login3(string login, string password)
    {
        string login1 = ConfigurationSettings.AppSettings["login3"];
        string password1 = ConfigurationSettings.AppSettings["password3"];
        if (login == login1 && password == password1)
        {
            return true;
        }
        return false;
    }

    ////vypis tabulku prislusniku
    public static DataTable SelectOsoba()
    {
        t = new DataTable();
        Query("Select * from Osoba;").Fill(t);
        return t;
    }
    //Insert
    public static void PridejOsoba(string Jmeno, string Prijmeni, string Povolani, int Poc_Det)
    {
        NonQuery("Insert into Osoba(Jmeno,Prijmeni,Povolani,Poc_Det) values('" + Jmeno + "','" + Prijmeni + "','" + Povolani + "','" + Poc_Det + "');");
    }
}

Answer 1

这个错误最有可能被抛出，因为您在此行中的连接：

return new SqlDataAdapter(command, Vrstva.myConnection);

尚未初始化。

在尝试查询之前，您必须先调用createConnectX()方法之一。

C＃错误：“填充：SelectCommand.Connection属性尚未初始化。”

1 个答案: