带有关闭和添加按钮的 TabControl

Question

我正在尝试使选项卡控件具有 "x"（关闭按钮）和“+”（新选项卡按钮）。我找到了添加 x button 的解决方案，现在选项卡如下所示：

但我想添加一个 + 现在那个黑色圆圈在哪里。我不知道如何，我尝试在最后一个选项卡的 Paint 事件上绘制，如下所示：

var p = tabs.TabPages[tabs.TabCount - 1];
p.Paint += new PaintEventHandler(tab_OnDrawPage);

private void tab_OnDrawPage(object sender, PaintEventArgs e)
{
    // e.ClipRectangle.
    e.Graphics.DrawString("+", 
                          new Font("verdana", 
                                   10, 
                                   FontStyle.Bold), 
                          Brushes.Black, 
                          e.ClipRectangle.X + 10, 
                          e.ClipRectangle.Y + 10);
}

但它没有显示任何平局。我想这与我传递给 DrawString() 调用的位置有关，但我不知道使用正确的位置。我用 +10 把它从最后一个选项卡上移开。如何解决？自己没画过定制图，正在学习中

Answer 1

通常，直接的 "low-level" 方法是处理 Paint 事件并绘制到 TabControl 本身，然后还处理鼠标输入事件检测您绘制的位置的点击。

但是，a) 这很痛苦，b) TabControl 抑制了 Paint 事件，所以如果不进入更低级别并处理 WM_PAINT WndProc() 方法覆盖中的消息。

出于您的目的，我建议您只添加一个新控件，例如a Button，到 Form，将其放在 TabControl 上您希望用户能够点击的地方。然后在 Button.Click 事件处理程序中，您可以根据需要添加一个新页面。如果要封装Button和TabControl的组合，可以使用UserControl.

例如：

TabControlWithAdd.Designer.cs:

partial class TabControlWithAdd
{
    /// <summary> 
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary> 
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Component Designer generated code

    /// <summary> 
    /// Required method for Designer support - do not modify 
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.button1 = new System.Windows.Forms.Button();
        this.tabControl1 = new System.Windows.Forms.TabControl();
        this.tabPage1 = new System.Windows.Forms.TabPage();
        this.tabPage2 = new System.Windows.Forms.TabPage();
        this.tabControl1.SuspendLayout();
        this.SuspendLayout();
        // 
        // button1
        // 
        this.button1.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
        this.button1.Location = new System.Drawing.Point(247, 3);
        this.button1.Name = "button1";
        this.button1.Size = new System.Drawing.Size(23, 23);
        this.button1.TabIndex = 0;
        this.button1.Text = "+";
        this.button1.UseVisualStyleBackColor = true;
        this.button1.Click += new System.EventHandler(this.button1_Click);
        // 
        // tabControl1
        // 
        this.tabControl1.Anchor = ((System.Windows.Forms.AnchorStyles)((((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Bottom) 
        | System.Windows.Forms.AnchorStyles.Left) 
        | System.Windows.Forms.AnchorStyles.Right)));
        this.tabControl1.Controls.Add(this.tabPage1);
        this.tabControl1.Controls.Add(this.tabPage2);
        this.tabControl1.Location = new System.Drawing.Point(3, 3);
        this.tabControl1.Name = "tabControl1";
        this.tabControl1.SelectedIndex = 0;
        this.tabControl1.Size = new System.Drawing.Size(267, 181);
        this.tabControl1.TabIndex = 1;
        // 
        // tabPage1
        // 
        this.tabPage1.Location = new System.Drawing.Point(4, 25);
        this.tabPage1.Name = "tabPage1";
        this.tabPage1.Padding = new System.Windows.Forms.Padding(3);
        this.tabPage1.Size = new System.Drawing.Size(259, 152);
        this.tabPage1.TabIndex = 0;
        this.tabPage1.Text = "tabPage1";
        this.tabPage1.UseVisualStyleBackColor = true;
        // 
        // tabPage2
        // 
        this.tabPage2.Location = new System.Drawing.Point(4, 25);
        this.tabPage2.Name = "tabPage2";
        this.tabPage2.Padding = new System.Windows.Forms.Padding(3);
        this.tabPage2.Size = new System.Drawing.Size(192, 71);
        this.tabPage2.TabIndex = 1;
        this.tabPage2.Text = "tabPage2";
        this.tabPage2.UseVisualStyleBackColor = true;
        // 
        // TabControlWithAdd
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 16F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.Controls.Add(this.button1);
        this.Controls.Add(this.tabControl1);
        this.Name = "TabControlWithAdd";
        this.Size = new System.Drawing.Size(273, 187);
        this.tabControl1.ResumeLayout(false);
        this.ResumeLayout(false);

    }

    #endregion

    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.TabControl tabControl1;
    private System.Windows.Forms.TabPage tabPage1;
    private System.Windows.Forms.TabPage tabPage2;
}

TabControlWithAdd.cs:

public partial class TabControlWithAdd : UserControl
{
    public TabControlWithAdd()
    {
        InitializeComponent();
    }

    private void button1_Click(object sender, EventArgs e)
    {
        tabControl1.TabPages.Add("Tab " + (tabControl1.TabPages.Count + 1));
    }
}

上面使用 Button，但当然你可以使用任何其他你喜欢的可点击控件，包括 Label（例如，如果你不想要按钮边框外观），来生成你想要的视觉效果

Answer 2

作为一个选项，您可以添加一个显示添加图标的额外选项卡，并检查用户何时单击该选项卡，然后在它之前插入一个新的 TabPage。

您还可以简单地使用 Selecting event of TabControl 来阻止选择额外的选项卡。这样最后一个选项卡对您来说就像一个添加按钮，就像 IE 和 Chrome.

实施细节

我们将使用所有者绘制选项卡在每个选项卡上显示关闭图标，在最后一个选项卡上显示添加图标。我们使用 DrawItem 关闭和添加图标，MouseDown 处理关闭和添加按钮的点击，Selecting 防止选择最后一个选项卡，HandleCreated 调整选项卡宽度.您可以在下面看到所有实施设置和代码。

初始化

设置填充和 DrawMode 并为 DrawItem、MouseDown、Selecting 和 HandleCreated 事件分配事件处理程序。

this.tabControl1.Padding = new Point(12, 4);
this.tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed;

this.tabControl1.DrawItem += tabControl1_DrawItem;
this.tabControl1.MouseDown += tabControl1_MouseDown;
this.tabControl1.Selecting += tabControl1_Selecting;
this.tabControl1.HandleCreated += tabControl1_HandleCreated;

处理关闭按钮和添加按钮的点击

您可以处理MouseDown或MouseClick事件并检查最后一个选项卡矩形是否包含鼠标单击点，然后在最后一个选项卡之前插入一个选项卡。否则检查是否其中一个关闭按钮包含点击位置，然后关闭其关闭按钮被点击的选项卡：

private void tabControl1_MouseDown(object sender, MouseEventArgs e)
{
    var lastIndex = this.tabControl1.TabCount - 1;
    if (this.tabControl1.GetTabRect(lastIndex).Contains(e.Location))
    {
        this.tabControl1.TabPages.Insert(lastIndex, "New Tab");
        this.tabControl1.SelectedIndex = lastIndex;
    }
    else
    {
        for (var i = 0; i < this.tabControl1.TabPages.Count; i++)
        {
            var tabRect = this.tabControl1.GetTabRect(i);
            tabRect.Inflate(-2, -2);
            var closeImage = Properties.Resources.DeleteButton_Image;
            var imageRect = new Rectangle(
                (tabRect.Right - closeImage.Width),
                tabRect.Top + (tabRect.Height - closeImage.Height) / 2,
                closeImage.Width,
                closeImage.Height);
            if (imageRect.Contains(e.Location))
            {
                this.tabControl1.TabPages.RemoveAt(i);
                break;
            }
        }
    }
}

防止选择最后一个选项卡

要防止选择最后一个标签，可以处理Selecting控件事件，检查选择的标签是否是最后一个标签，取消事件：

private void tabControl1_Selecting(object sender, TabControlCancelEventArgs e)
{
    if (e.TabPageIndex == this.tabControl1.TabCount - 1)
        e.Cancel = true;
}

绘制关闭按钮和添加按钮

绘制关闭按钮和添加按钮，可以处理DrawItem事件。我将这些图标用于添加和关闭按钮。

private void tabControl1_DrawItem(object sender, DrawItemEventArgs e)
{
    var tabPage = this.tabControl1.TabPages[e.Index];
    var tabRect = this.tabControl1.GetTabRect(e.Index);
    tabRect.Inflate(-2, -2);
    if (e.Index == this.tabControl1.TabCount - 1)
    {
        var addImage = Properties.Resources.AddButton_Image;
        e.Graphics.DrawImage(addImage,
            tabRect.Left + (tabRect.Width - addImage.Width) / 2,
            tabRect.Top + (tabRect.Height - addImage.Height) / 2);
    }
    else
    {
        var closeImage = Properties.Resources.DeleteButton_Image;
        e.Graphics.DrawImage(closeImage,
            (tabRect.Right - closeImage.Width),
            tabRect.Top + (tabRect.Height - closeImage.Height) / 2);
        TextRenderer.DrawText(e.Graphics, tabPage.Text, tabPage.Font,
            tabRect, tabPage.ForeColor, TextFormatFlags.Left);
    }
}

调整标签宽度

要调整选项卡宽度并让最后一个选项卡的宽度更小，您可以处理 HandleCreated 事件并向控件发送 TCM_SETMINTABWIDTH 并指定选项卡宽度允许的最小尺寸：

[DllImport("user32.dll")]
private static extern IntPtr SendMessage(IntPtr hWnd, int msg, IntPtr wp, IntPtr lp);
private const int TCM_SETMINTABWIDTH = 0x1300 + 49;
private void tabControl1_HandleCreated(object sender, EventArgs e)
{
    SendMessage(this.tabControl1.Handle, TCM_SETMINTABWIDTH, IntPtr.Zero, (IntPtr)16);
}

下载

您可以在此处下载代码或克隆存储库：

r-aghaei/TabControlWithCloseButtonAndAddButton

Answer 3

另一种解决方法是创建一个新的 TabControl 来扩展 TabControl class。我曾经遇到过同样的问题，我就是这样做的，我找不到完成的代码，但这可以在您的选项卡中添加 X，同样可以应用于 +签名：

public delegate bool PreRemoveTab(int indx);
public class TabControlEx : TabControl
{
    public TabControlEx()
        : base()
    {
        PreRemoveTabPage = null;
        this.DrawMode = TabDrawMode.OwnerDrawFixed;
    }

    public PreRemoveTab PreRemoveTabPage;

    protected const int size = 5;

    protected int moveRight = 0;

    protected int MoveRight
    {
        get { return moveRight; }
        set { moveRight = value; }
    }

    protected override void OnDrawItem(DrawItemEventArgs e)
    {
        Brush b = new SolidBrush(Color.Salmon);
        Brush b1 = new SolidBrush(Color.Black);
        Font f = this.Font;
        Font f1 = new Font("Arial", 9,FontStyle.Bold);
        if (e.Index != 0)
        {
            Rectangle r = e.Bounds;
            r = GetTabRect(e.Index);
            r.Offset(2, 2);
            r.Width = size;
            r.Height = size;               
            Pen p = new Pen(b,2);
            string title = this.TabPages[e.Index].Text;               
            string boldLetter = title.Substring(0, 1);
            title = title.Remove(0, 1);
            MoveRight = ((Int32)e.Graphics.MeasureString(title, f, 200).Width) + 1;   // -1
            e.Graphics.DrawLine(p, r.X +10 + MoveRight - 2, r.Y, r.X +10 + MoveRight + r.Width, r.Y + r.Height+2);
            e.Graphics.DrawLine(p, r.X +10 + MoveRight + r.Width, r.Y, r.X + 10 + MoveRight-2, r.Y + r.Height+2);
            e.Graphics.DrawString(boldLetter, f1, b1, new PointF(r.X, r.Y));
            e.Graphics.DrawString(title, f, b1, new PointF(r.X+8, r.Y+1));    
        }
        else
        {
            Rectangle r = GetTabRect(e.Index);
            e.Graphics.DrawString(this.TabPages[e.Index].Text, f, b1, new PointF(r.X + 5, r.Y));
        }
    }

    protected override void OnMouseClick(MouseEventArgs e)
    {
        Point p = e.Location;
        for (int i = 0; i < TabCount; i++)
        {
            Rectangle r = GetTabRect(i);
            r.Offset(2, 2);
            r.Width = size+2;
            r.Height = size+2;
            r.X = r.X + MoveRight + 8;
            if (r.Contains(p))
            {
                if (i != 0)
                {
                    CloseTab(i);
                }
            }
        }
    }

    private void CloseTab(int i)
    {
        if (PreRemoveTabPage != null)
        {
            bool closeIt = PreRemoveTabPage(i);
            if (!closeIt)
                return;
        }
        TabPages.Remove(TabPages[i]);
    }
}

您可以尝试稍微修改一下，直到它适合您的需要。

带有关闭和添加按钮的 TabControl

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