将控件垂直和水平保持在其容器的中心 [英] Keep a Control vertically and horizontally at center of its container

问题描述

我尝试创建一个带有边框的自定义面板，其颜色可以更改，以便在某些情况下"突出显示"面板。

专家组还需要通过文本传达某些信息。为此，我向面板添加了一个标签。我尝试了规定的使标签居中的方法，但由于某种原因，标签总是放在面板的左上角。我不能将标签的Dock设置为Fill，因为这会覆盖已创建的自定义边框。因此，我需要使标签适合边框。

标签的Anchor设置为None，其位置为

new Point((ClientSize.Width - Size.Width)/2, (ClientSize.Height - Size.Height)/2);

自定义面板的代码为：

public class CustomPanel : Panel
{
    public CustomPanel(int borderThickness, Color borderColor) : base()
    {
        SetStyle(ControlStyles.AllPaintingInWmPaint | 
                 ControlStyles.UserPaint | 
                 ControlStyles.OptimizedDoubleBuffer | 
                 ControlStyles.ResizeRedraw, true);

        BackColor = SystemColors.ActiveCaption;
        BorderStyle = BorderStyle.FixedSingle;
        Size = new Size(45, 45);
        Margin = new Padding(0);
        BorderThickness = borderThickness;
        BorderColor = borderColor;
    }

    protected override void OnPaint(PaintEventArgs e)
    {
        base.OnPaint(e);

        if (BorderStyle == BorderStyle.FixedSingle)
        {
            int halfThickness = BorderThickness / 2;
            using (Pen p = new Pen(BorderColor, BorderThickness))
            {
                e.Graphics.DrawRectangle(p, new Rectangle(halfThickness,
                     halfThickness,
                     ClientSize.Width - BorderThickness, ClientSize.Height - BorderThickness));
            }
        }
    }

    public int BorderThickness { get; set; }
    public Color BorderColor { get; set; }
}

表单代码为：

private void NewPanelTest_Load(object sender, EventArgs e)
{
    CustomPanel cp = new CustomPanel(3, Color.Black);

    // Create new Label
    Label info = new Label()
    {
        Size = new Size(30, 30),
        Text = "Info",
        Anchor = AnchorStyles.None,
        TextAlign = ContentAlignment.MiddleCenter,
        Enabled = false,
        Font = new Font("Microsoft Sans Serif", 6),
        ForeColor = Color.White,
        Location = new Point(ClientSize.Width/2 - Width/2, ClientSize.Height/2 - Height/2)
    };

    cp.Controls.Add(info);

    this.Controls.Add(cp);
}

编辑：我已经查看过提出的类似问题，并尝试更改标签的属性，但没有结果。

// Create new Label
Label info = new Label()
{
    // Same code as before

    // Different code
    Left = (this.ClientSize.Width - Size.Width) / 2,
    Top = (this.ClientSize.Height - Size.Height) / 2,
    //Location = new Point(ClientSize.Width/2 - Width/2, ClientSize.Height/2 - Height/2)
};

我还尝试更改面板的填充，也没有结果。

Padding = new Padding(5);

编辑：尝试以编程方式将标签放置在面板中心(结果为X=0，Y=0)

// Create new Label
Label info = new Label()
{
    // Same code as before (excluding "Left", "Top", and "Location")
};
int X = (info.ClientSize.Width - info.Width) / 2;
int Y = (info.ClientSize.Height - info.Height) / 2;
info.Location = new Point(X, Y);
MessageBox.Show(info.Location.ToString());

cp.Controls.Add(info);

推荐答案

我们可以通过简单的步骤实现这一点

• 将标签锚定设置为左右
• 将标签自动调整大小设置为False；
• 将标签TextAlign设置为MiddleCenter；

现在将标签放在面板的中间。

   int x = (panel1.Size.Width - label1.Size.Width) / 2;
    label1.Location = new Point(x, label1.Location.Y);

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