Question

我有一个win form表单应用程序，其中列表框显示方法（按属性）。我试图动态调用线程中的方法，使用反射从列表框的选定值获取方法信息。但是，当调用 Methodinfo.Invoke 时，我得到了这个内部异常“非静态方法需要一个目标C＃”。

这是我的代码（请记住，我仍然是c＃和编程的新手。）

private void PopulateComboBox()
{//Populates list box by getting methods with declared attributes
    MethodInfo[] methods = typeof(MainForm).GetMethods();

    MyToken token = null;
    List<KeyValuePair<String, MethodInfo>> items =
        new List<KeyValuePair<string, MethodInfo>>();

    foreach (MethodInfo method in methods)
    {
        token = Attribute.GetCustomAttribute(method,
            typeof(MyToken), false) as MyToken;
        if (token == null)
            continue;

        items.Add(new KeyValuePair<String, MethodInfo>(
            token.DisplayName, method));

    }

    testListBox.DataSource = items;
    testListBox.DisplayMember = "Key";
    testListBox.ValueMember = "Value";
}

public void GetTest()
{//The next two methods handle selected value of the listbox and invoke the method.

    if (testListBox.InvokeRequired)
        testListBox.BeginInvoke(new DelegateForTest(functionForTestListBox));
    else
        functionForTestListBox();

}

public void functionForTestListBox()
{
    _t = testListBox.SelectedIndex;

    if (_t < 0)
        return;

    _v = testListBox.SelectedValue;

    method = _v as MethodInfo;


    if (method == null)
        return;

    _selectedMethod = method.Name;

    MessageBox.Show(_selectedMethod.ToString());

    method.Invoke(null, null);//<----Not sure about this. it runs fine when I dont invoke in a thread.

    counter++;

}
private void runTestButton_Click(object sender, EventArgs e)
{// Click event that calls the selected method in the thread
    if (_serverStatus == "Running")
    {

        if (_testStatus == "Not Running")
        {

            // create Instance new Thread and add function
            // which will do some work
            try
            {
                SetupTestEnv();
                //functionForOutputTextBox();
                Thread UIthread = new Thread(new ThreadStart(GetTest));
                UIthread.Name = "UIThread";
                UIthread.Start();
                // Update test status
                _testStatus = "Running";
                //Make thread global
                _UIthread = UIthread;
            }
            catch
            {
                    MessageBox.Show("There was an error at during the test setup(Note: You must install each web browser on your local machine before attempting to test on them).");
            }

        }
        else
        {
            MessageBox.Show("Please stop the current test before attempt to start a new one");
        }
    }
    else
    {
        MessageBox.Show("Please make sure the server is running");
    }
}

Answer 1

您试图在不提供对象实例引用的情况下调用非静态方法，应该为此方法调用此方法。由于您正在使用MainForm类的方法，因此您应该在MainForm的第一个参数中提供MethodInfo.Invoke(Object, Object[])类型的对象，在您的情况下：

if(method.IsStatic)
    method.Invoke(null, null);
else
    method.Invoke(this, null);

在单独的线程上执行方法的示例：

public MethodInfo GetSelectedMethod()
{
    var index = testListBox.SelectedIndex;
    if (index < 0) return;
    var value = testListBox.SelectedValue;
    return value as MethodInfo;
}

private void ThreadProc(object arg)
{
    var method = (MethodInfo)arg;
    if(method.IsStatic)
        method.Invoke(null, null)
    else
        method.Invoke(this, null);
}

private void RunThread()
{
    var method = GetSelectedMethod();
    if(method == null) return;
    var thread = new Thread(ThreadProc)
    {
        Name = "UIThread",
    };
    thread.Start(method);
}

非静态方法需要目标C＃

1 个答案: