助记符按钮触发 按钮的单击事件，但它未触发 离开文本框的事件

Question

我有一个Windows窗体与几个文本框和一个按钮。按钮有一个助记键来触发(示例&OK)。我订阅了TextBox的Leave事件，以便根据用户输入进行验证并更新相关控件(例如，如果我更改了产品的成本，则可租赁性比例将被更新)。如果我单击OK按钮，一切正常，但如果我使用助记键(Alt+O)，则在按钮的click事件之后触发TextBox的Leave事件。因此，我的文本框在按钮的Click事件之前不会更新。什么好主意吗?

正常行为总结:-更新文本框值并单击OK按钮->文本框触发离开事件并更新值。的Click事件被处理。

奇怪行为总结:-更新文本框的值并按下确定按钮的快捷键(Alt+O) -->单击按钮的事件被触发，然后文本框的离开事件被触发。

Answer 1

试一试…

Dim sButtonBy as String
Private Sub TextBox1_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.GotFocus      
    sButtonBy = ""
End Sub
Private Sub TextBox1_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles TextBox1.KeyDown
    If e.Alt Then sButtonBy = "KB"
End Sub
Private Sub TextBox1_Leave(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox1.Leave
    UpdateIt()
End Sub
Sub UpdateIt()
    'codes here
End Sub

编辑:

Use this sub to handle every button that added dynamically
AddHandler Button1.Click, AddressOf Me.Buttons_Click
Private Sub Buttons_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)
    If sButtonBy = "KB" Then updateit()
    'codes here
End Sub

Answer 2

您可以使用"LostFocus"事件代替"Leave"…

Answer 3

我终于找到了一个使用来自不同地方的代码片段的解决方案。我认为把它写下来很重要因为我还没有找到完整的答案。甚至与这个问题相关的问题也很难找到。让我解释一下我做了什么:

1)重写表单中的ProcessMnemonic方法。

        protected override bool ProcessMnemonic(char charCode)
        {
            // get the mnemonic key of the button that submits the form (accepts the form or performs some action)
            char mnemonicChar = DesignerHelper.GetMnemonicChar(btnCreate);
            // check if the button has a mnemonic key and if the mnemonic key pressed corresponds to it
            if (mnemonicChar != ' ' && charCode == mnemonicChar)
            {
            // get the control that is focused. this could be the textbox where the mnemonic key was pressed
                Control ctrl = DesignerHelper.FindFocusedControl(this);
                if (ctrl != null)
                {
                // fire the necessary event to update the state of the controls. in my case it's leave event.
                    DesignerHelper.FireEvent(ctrl, "Leave", new EventArgs());
                }
            }
            return base.ProcessMnemonic(charCode);
        }

2)在我自己的DesignerHelper类中可用的方法:

        public static Control FindFocusedControl(Control control)
        {
            var container = control as ContainerControl;
            while (container != null)
            {
                control = container.ActiveControl;
                container = control as ContainerControl;
            }
            return control;
        }
        /// <summary>
        /// Programatically fire an event handler of an object
        /// </summary>
        /// <param name="targetObject"></param>
        /// <param name="eventName"></param>
        /// <param name="e"></param>
        public static void FireEvent(Object targetObject, string eventName, EventArgs e)
        {
            /*
             * By convention event handlers are internally called by a protected
             * method called OnEventName
             * e.g.
             *     public event TextChanged
             * is triggered by
             *     protected void OnTextChanged
             * 
             * If the object didn't create an OnXxxx protected method,
             * then you're screwed. But your alternative was over override
             * the method and call it - so you'd be screwed the other way too.
             */
            //Event thrower method name //e.g. OnTextChanged
            String methodName = "On" + eventName;
            MethodInfo mi = targetObject.GetType().GetMethod(
                  methodName,
                  BindingFlags.Instance | BindingFlags.NonPublic);
            if (mi == null)
                throw new ArgumentException("Cannot find event thrower named " + methodName);
            mi.Invoke(targetObject, new object[] { e });
        }
        internal static char GetMnemonicChar(Button btn)
        {
            if (btn.UseMnemonic && btn.Text.Contains("&"))
            {
                return btn.Text.Substring(btn.Text.IndexOf("&") + 1, 1)[0];
            }
            return ' ';
        }