防止只读 RichTextBox 出现闪烁光标 (IBeam)

Question

每当文本框获得焦点时，是否有办法防止只读 RichRextBox 的光标（IBeam）闪烁？

我尝试阻止来自 WndProc 的 WM_SETFOCUS 消息，但它导致表单挂起。

if( m.Msg == 0x0007 ) return;

Answer 1

您需要使用 Win32 API。 以下是您可以在 VB 中执行的操作：

'API declares
Private Declare Function HideCaret Lib "user32" _
(ByVal hwnd As IntPtr) As Integer
Private Declare Function ShowCaret Lib "user32" _
(ByVal hwnd As IntPtr) As Integer
'hide the caret in myTextBox
Call HideCaret(myTextBox.Handle)
'show the caret back..
Call ShowCaret(myTextBox.Handle)

在 C# 中，

 [DllImport("user32.dll", EntryPoint = "ShowCaret")]
 public static extern long ShowCaret(IntPtr hwnd);
 [DllImport("user32.dll", EntryPoint = "HideCaret")]
 public static extern long HideCaret(IntPtr hwnd);

进行调用。

   HideCaret(richtextbox.Handle)

然后在您想要隐藏它时

Answer 2

只是说 Anirudh Goel 的答案不起作用（至少在 C# 中）。 克拉仍然闪烁：/

我在以下位置找到了解决方案： http://www.experts-exchange .com/Programming/Languages/C_Sharp/Q_21896403.html

他的类总是隐藏插入符号，这里是一个改进的类，因此您可以选择隐藏或不隐藏插入符号。

如果你想隐藏，请不要忘记将 MustHideCaret 设置为 true

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace Lm
{
    public class RichTextBoxEx : RichTextBox
    {
        private readonly object mustHideCaretLocker = new object();

        private bool mustHideCaret;

        [DefaultValue(false)]
        public bool MustHideCaret
        {
            get
            {
                lock (this.mustHideCaretLocker)
                    return this.mustHideCaret;
            }
            set
            {
                TabStop = false;
                if (value)
                    SetHideCaret();
                else
                    SetShowCaret();
            }
        }

        [DllImport("user32.dll")]
        private static extern int HideCaret(IntPtr hwnd);
        [DllImport("user32.dll", EntryPoint = "ShowCaret")]
        public static extern long ShowCaret(IntPtr hwnd);

        public RichTextBoxEx()
        {
        }

        private void SetHideCaret()
        {
            MouseDown += new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
            MouseUp += new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
            Resize += new EventHandler(ReadOnlyRichTextBox_Resize);
            HideCaret(Handle);
            lock (this.mustHideCaretLocker)
                this.mustHideCaret = true;
        }

        private void SetShowCaret()
        {
            try
            {
                MouseDown -= new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
                MouseUp -= new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
                Resize -= new EventHandler(ReadOnlyRichTextBox_Resize);
            }
            catch
            {
            }
            ShowCaret(Handle);
            lock (this.mustHideCaretLocker)
                this.mustHideCaret = false;
        }

        protected override void OnGotFocus(EventArgs e)
        {
            if (MustHideCaret)
                HideCaret(Handle);
        }

        protected override void OnEnter(EventArgs e)
        {
            if (MustHideCaret)
                HideCaret(Handle);
        }

        private void ReadOnlyRichTextBox_Mouse(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            HideCaret(Handle);
        }

        private void ReadOnlyRichTextBox_Resize(object sender, System.EventArgs e)
        {
            HideCaret(Handle);
        }
    }
}

Answer 3

更简单的方法：将此事件附加到 RichTextBox 的 Enter 事件中：

  private void Control_Enter(object sender, EventArgs e) {
    ActiveControl = null;
  }

Answer 4

对我来说 Pedro77 的解决方案也不起作用......
我已将该类修改为：

using System;
using System.ComponentModel;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace Lm
{
    public class RichTextBoxEx : RichTextBox
    {
        private readonly object mustHideCaretLocker = new object();

        private bool mustHideCaret;

        [DefaultValue(false)]
        public bool MustHideCaret
        {
            get
            {
                lock (this.mustHideCaretLocker)
                    return this.mustHideCaret;
            }
            set
            {
                TabStop = false;
                if (value)
                    SetHideCaret();
                else
                    SetShowCaret();
            }
        }

        [DllImport("user32.dll")]
        private static extern int HideCaret(IntPtr hwnd);
        [DllImport("user32.dll", EntryPoint = "ShowCaret")]
        public static extern long ShowCaret(IntPtr hwnd);

        public RichTextBoxEx()
        {
        }

        private void SetHideCaret()
        {
            MouseDown += new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
            MouseUp += new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
            Resize += new EventHandler(ReadOnlyRichTextBox_Resize);
            HideCaret(Handle);
            lock (this.mustHideCaretLocker)
                this.mustHideCaret = true;
        }

        private void SetShowCaret()
        {
            try
            {
                MouseDown -= new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
                MouseUp -= new MouseEventHandler(ReadOnlyRichTextBox_Mouse);
                Resize -= new EventHandler(ReadOnlyRichTextBox_Resize);
            }
            catch
            {
            }
            ShowCaret(Handle);
            lock (this.mustHideCaretLocker)
                this.mustHideCaret = false;
        }

        protected override void OnGotFocus(EventArgs e)
        {
            if (MustHideCaret)
            {
                HideCaret(Handle);
                this.Parent.Focus();//here we select parent control in my case it is panel
            }
        }

        protected override void OnEnter(EventArgs e)
        {
            if (MustHideCaret)
                HideCaret(Handle);
        }

        private void ReadOnlyRichTextBox_Mouse(object sender, System.Windows.Forms.MouseEventArgs e)
        {
            HideCaret(Handle);
        }

        private void ReadOnlyRichTextBox_Resize(object sender, System.EventArgs e)
        {
            HideCaret(Handle);
        }
    }
}

然后将我的 RichTextBoxEx 放入（内部）面板控件中...
修复了单击鼠标时闪烁插入符号的问题...

Answer 5

经过多次尝试和错误，我找到了简单的解决方案。

在表单的“加载”子例程中，添加以下行：

AddFocusHandlers(Me)

然后将以下内容添加到表单代码的底部。 规定您希望在“HideCaret”例程中发生“阻止进入”的控件
（我列出了属于我的表单的三个文本框）：

Private Sub AddFocusHandlers(ByVal parentCtr As Control)
    Dim ctr As Control
    For Each ctr In parentCtr.Controls
        AddHandler ctr.LostFocus, AddressOf meLostFocus
        AddFocusHandlers(ctr)
    Next
End Sub

Private Sub meLostFocus(ByVal sender As Object, ByVal e As System.EventArgs)
    LastFocused = DirectCast(sender, Control)
End Sub

'This routine will activate each time any of the listed controls are entered.
Private Sub HideCaret(sender As Object, e As EventArgs) _
               Handles tbDate.Enter, tbAttachments.Enter, tbTemplate.Enter
    LastFocused.Select()
End Sub

最后将其放置在表单代码的顶部（在类名称和第一个子或函数之间）：

    Private LastFocused As Control  'Control which previously had focus

然后，当用户单击控件列表中显示的任何控件时在“HideCaret”例程中，光标只是停留在先前选择的控件中。
VB.Net 不是很棒吗？ 你几乎可以实现任何你认为不可能的事情。