禁止 win 文本框编辑和选择

Question

做一个客户的项目，他们提出了一个奇怪的要求。他们希望在 winform（vb.net 或 c#）中有一个功能，当显示模式打开时，没有文本框可以编辑和选择。我知道将 enabled 属性更改为 false 将解决它，但他们希望它处于活动状态但不可选择。谁能给我一些想法？

Answer 1

我从您对另一个答案的评论中看到您选择了控件交换解决方案。但是，我认为以下内容可能对寻求类似行为的人有用。

此控件不会阻止对 TextBox 控件的编程选择，但会阻止用户通过鼠标和键盘进行正常选择。使用Selectable 属性启用/禁用选择。

Public Class TB : Inherits TextBox
    Public Sub New()
        SetStyle(ControlStyles.Selectable, False)
    End Sub

    Public Property Selectable As Boolean
        Get
            Return GetStyle(ControlStyles.Selectable)
        End Get
        Set(value As Boolean)
            SetStyle(ControlStyles.Selectable, value)
        End Set
    End Property

    Private Const WM_MOUSEACTIVATE As Integer = &H21
    Private Const NOACTIVATEANDEAT As Integer = &H4

     Protected Overrides Sub WndProc(ByRef m As Message)
        If m.Msg = WM_MOUSEACTIVATE AndAlso Not Me.Selectable Then
            m.Result = New IntPtr(NOACTIVATEANDEAT)
            Return
        End If
        MyBase.WndProc(m)
     End Sub
End Class

Answer 2

我猜你需要重写 onPaint 事件！

如果我没记错的话，这应该是这么简单，不需要创建自定义控件，只需打开表单设计器文件并使用以下内容：

Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
        MyBase.OnPaint(e)
        TextBox1.BackColor = Color.White
End Sub

您可以循环所有应该很容易的控件。

Answer 3

虽然 TnTinMn 已经解决了我的问题，但我得到了一个关于保持文本框的文本颜色完整的很好的链接，并且可能是关于如何采用新方法来解决这个问题的令人惊叹的事情。 链接在这里， https://www.experts-exchange.com/articles/10842/A-New-Approach-for-Custom-Colors-in-a-Disabled-VB-Net-WinForms-TextBox.html 作者 Mike Tomlinson 非常详细地介绍了他在帖子中所写的每一个步骤。

TnTinMn 方法对于解决这类问题也很有用。

Answer 4

/*Here is the full code of new text box control.
Inspired by the Post made by Mike Tomlinson and Ehtesham*/
using System;
using System.Drawing;
using System.Windows.Forms;
using System.ComponentModel;
namespace MyTxtBoxControl
{
public class extTextBox:TextBox
{
#region New Utilisable Variables
    const int WM_ENABLE = 0xa; //in vb &HA
    Color _foreColor;
    Color _foreColorDisabled;
    Boolean _ColorIsSaved = false;
    Boolean _settingColor = false;
    //included a default text
    //that will be shown when no text will be entered
    String _DefaultText = "Enter Text Here";
#endregion
#region Constructor of the new textbox control
    public extTextBox()
    {
        base.Text = this._DefaultText;
        this._foreColor = this.ForeColor;
        //My Text Control Box event handlers
        this.TextChanged += new EventHandler(onTextChanged);
        this.KeyPress += new KeyPressEventHandler(onKeyPress);
        this.LostFocus += new EventHandler(onTextChanged);
        this.VisibleChanged+=new EventHandler(onVisibleChanged);
    }
#endregion
#region Event Handler Methods
    protected void onTextChanged(object sender, EventArgs e)
        {
            if (!String.IsNullOrEmpty(this.Text))
            {
                this.ForeColor = this._foreColor;
            }
            else
            {
                this.TextChanged-=new EventHandler(onTextChanged);
                base.Text = this._DefaultText;
                this.TextChanged+=new EventHandler(onTextChanged);
            }
        }
        protected void onKeyPress(object sender, EventArgs e)
        {
            //Replaces empty text as the firt key will be pressed
            string strings = base.Text.Replace(this._DefaultText, string.Empty);
            this.TextChanged -= new EventHandler(onTextChanged);
            this.Text=strings;
            this.TextChanged += new EventHandler(onTextChanged);
        }
        protected void onVisibleChanged(object sender, EventArgs e)
        {
            if (!(this._ColorIsSaved & this.Visible))
            {
                _foreColor = this.ForeColor;
                _foreColorDisabled = this.ForeColor;
                _ColorIsSaved = true;

                if (!(this.Enabled))
                {
                    this.Enabled = true; //Enable to initialize the property then
                    this.Enabled = false;//disabling 
                }
                setColor();
            }
        }

        protected override void OnForeColorChanged(EventArgs e)
        {
            base.OnForeColorChanged(e);
            if (!_settingColor)
            {
                _foreColor = this.ForeColor;
                setColor();
            }
        }
        protected override void OnEnabledChanged(EventArgs e)
        {
            base.OnEnabledChanged(e);
            setColor();
        }
#endregion
#region Setcolor method
        private void setColor()
        {
            if (_ColorIsSaved)
            {
                _settingColor = true;
                if (this.Enabled)
                {
                    this.ForeColor = this._foreColor;
                }
                else
                {
                    this.ForeColor = this._foreColorDisabled;
                }
                _settingColor = false;
            }
        }
#endregion
#region TextBox Encapsulation Parameter overriding 
        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams CP = default(CreateParams);
                if (!this.Enabled)
                {
                    this.Enabled = true;
                    CP = base.CreateParams;
                    this.Enabled = false;
                }
                else
                {
                    CP = base.CreateParams;
                }
                return CP;
            }
        }
#endregion
#region supressing WM_ENABLE message
        protected override void WndProc(ref Message mesg)
        {
            switch (mesg.Msg)
            {
                case WM_ENABLE:
               // Prevent the message from reaching the control,
               // so the colors don't get changed by the default procedure.
                    return;// <-- suppress WM_ENABLE message
            }
            base.WndProc(ref mesg);//system you can do the rest disable process
        }
#endregion
#region User Defined Properties
        ///<summery>
        ///Property to set Text
        ///</summery>
        [Browsable(true)]
        [Category("Properties")]
        [Description("Set TextBox Text")]
        [DisplayName("Text")]
        public new String Text
        {
            get
            {
                //It is required for validation for TextProperty
                return base.Text.Replace(this._DefaultText, String.Empty);
            }
            set
            {
                base.Text = value;
            }
        }
        ///<summery>
        ///Property to get or Set Default text at Design/Runtime
        ///</summery>
        [Browsable(true)]
        [Category("Properties")]
        [Description("Set default Text of TextBox, it will be shown when no text will be entered by the user")]
        [DisplayName("Default Text")]
        public String DefaultText
        {
            get
            {
                return this._DefaultText;
            }
            set
            {
                this._DefaultText = value;
                base.OnTextChanged(new EventArgs());
            }
        }
#endregion
}

}