C# Winform编程自定义控件(UserControl)可自适应大小的TextBox复合控件

一个C# Winform自定义控件(UserControl)MyTextBox,实现功能:

  1. 窗体大小变化时重新计算自身位置,始终保持在居中状态。
  2. 自定义键盘回车事件,回车键触发时,调用用户传递的回调。
  3. 不使用*.Designer.cs文件,直接放在*.cs中。
  4. 重写控件属性Text与BackColor

直接上代码:

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using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace BubbleMessage
{
public class MyTextBox : UserControl
{
public MyTextBox()
{
InitializeComponent();
}

protected override void OnLayout(LayoutEventArgs e)
{
base.OnLayout(e);

//获取子控件
if (this.Controls.Count == 0) return;
Control c = this.Controls[0];

//父窗口参数
Padding p = this.Padding;
int x = 0, y = 0;
int w = this.Width, h = this.Height;
w -= (p.Left + p.Right);
x += p.Left;

//计算文本框的高度,使其显示在中间
int h2 = c.PreferredSize.Height;
if (h2 > h) h2 = h;
y = (h - h2) / 2;

c.Location = new Point(x, y);
c.Size = new Size(w, h2);
}


public event EventHandler ReturnPressed;

/// <summary>
/// 必需的设计器变量。
/// </summary>
private System.ComponentModel.IContainer components = null;

/// <summary>
/// 清理所有正在使用的资源。
/// </summary>
/// <param name="disposing">如果应释放托管资源,为 true;否则为 false。</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}

#region 组件设计器生成的代码

/// <summary>
/// 设计器支持所需的方法 - 不要修改
/// 使用代码编辑器修改此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.edit = new System.Windows.Forms.TextBox();
this.SuspendLayout();
//
// edit
//
this.edit.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.edit.BackColor = System.Drawing.Color.White;
this.edit.BorderStyle = System.Windows.Forms.BorderStyle.None;
this.edit.Location = new System.Drawing.Point(3, 17);
this.edit.Name = "edit";
this.edit.Size = new System.Drawing.Size(336, 18);
this.edit.TabIndex = 0;
this.edit.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.edit_KeyPress);
//
// MyTextBox
//
this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 15F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.BackColor = System.Drawing.Color.White;
this.Controls.Add(this.edit);
this.Name = "MyTextBox";
this.Size = new System.Drawing.Size(344, 53);
this.ResumeLayout(false);
this.PerformLayout();

}

#endregion

private System.Windows.Forms.TextBox edit;

private void edit_KeyPress(object sender, KeyPressEventArgs e)
{
if (e.KeyChar == '\r')
{
ReturnPressed?.Invoke(this, e);
}
}

public override string Text
{
get { return edit.Text; }
set
{
edit.Text = value;
}
}


public override Color BackColor
{
get { return base.BackColor; }
set
{
edit.BackColor = value;
base.BackColor = value;
}
}
}
}

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