Question

我有一个我试图在另一个程序中使用的DLL。这是导致一些问题的部分：

来自我的dll：

public class fService
{
    public static readonly string connectionString = "My connection string";
    ...
    etc
    ...
    public static void myStaticMethod()
    {
        fStat x = new fStat();
    }
}

来自我的其他计划：

private void btnSave_Click(object sender, EventArgs e)
{
    try
    {
        fService.myStaticMethod();
        MessageBox.Show("Success!");
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

我得到的例外是The ConnectionString property has not been initialized.。

这是为什么？如何正确初始化？将fService类定为静态（我想避免这种情况）？

堆栈跟踪：

at System.Data.SqlClient.SqlConnection.PermissionDemand()
   at System.Data.SqlClient.SqlConnectionFactory.PermissionDemand(DbConnection outerConnection)
   at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
   at System.Data.SqlClient.SqlConnection.Open()
   at fManager.tableClasses.fStats..ctor() in e:\fManager\project\fManager\ConsoleApplication1\tableClasses\fStats.cs:line 55
   at fManager.fService.constructElement(String header, String content, fService& service) in e:\fManager\project\fManager\ConsoleApplication1\fService.cs:line 964
   at fManager.fService.LoadIni(String path) in e:\fManager\project\fManager\ConsoleApplication1\fService.cs:line 675
   at fManagerF.mainForm.btnSave_Click(Object sender, EventArgs e) in e:\fManager\exeProject\fManagerF\fManager\mainForm.cs:line 54

这就是问题的根源所在：

public fStat()
{
    using (SqlConnection conn = new SqlConnection(connectionString))
    {
        SqlCommand cmd = new SqlCommand("fManager.getfStats", conn);
        SqlCommand cmdCount = new SqlCommand("SELECT COUNT(*) FROM [fManager].[fStats]", conn);
        _id = 0;
        cmd.CommandType = System.Data.CommandType.StoredProcedure;
        conn.Open();
        _id = (int)cmdCount.ExecuteScalar();
        cmd.ExecuteNonQuery();
        conn.Close();
    }
}

编辑：如果你downvote / vote关闭，请告诉我原因。我觉得我已经提供了所有信息并且我保持在topid上，但请通过让我知道我失败的地方帮助我改进=）

Answer 1

您将connectionString属性定义为fService类的静态成员，但在connectionString类中使用变量fStat。这不是同一个变量。您的fService.connectionString已初始化，fStat.connectionString未初始化。同样，ConnectionString中的SqlConnection也未初始化，因此错误。

静态只读变量未在DLL中初始化

1 个答案: