玩转控件:封装个带图片的Label控件
话不多说,先看效果
经常做工控上位机或者MES的都知道,UI虽然没有要求那么高,实用就好,但是能美化下winform UI 有时候也能给客户增加几分好感,给枯燥乏味的工作增添一抹颜色

起因
为了给枯燥UI添加点颜色,前后也找了很多UI控件,免费里面效果最好(实际很拉跨)的也就RealTaiizor了,但是集成过的同学们都应该知道,稍微后台逻辑复杂一点,耗时就一点的,加载起来贼慢,而且很容易整个控件崩溃,一个大大的红X
ImageLabel
惹不起,还躲不起吗?RealTaiizor效果好看,那就按照它的效果,重新封装一个简化版控件,能满足实际业务需求即可!开始动手,继承Label控件,扩展图片显示位置,图片大小,图片和文字间距,图片更改事件等等功能

[ToolboxBitmap(typeof(Label))]
publicpartialclassImageLabel : Label
{
private Image _image;
privateint _imageWidth = 32;
privateint _imageHeight = 32;
privateint _imageTextSpacing = 5;
private ContentAlignment _imageAlign = ContentAlignment.MiddleLeft; // 默认图片左中对齐
publicImageLabel()
{
this.DoubleClick += ImageLabel_DoubleClick;
// 确保控件支持透明背景(如果需要)
this.SetStyle(ControlStyles.SupportsTransparentBackColor | ControlStyles.ResizeRedraw, true);
}
#region Public Properties
[Category("Appearance")]
[Description("The image displayed.")]
public Image Image
{
get { return _image; }
set
{
_image = value;
Invalidate();
OnImageChanged(EventArgs.Empty);
}
}
[Category("Appearance")]
[DefaultValue(32)]
publicint ImageWidth
{
get { return _imageWidth; }
set
{
_imageWidth = value;
Invalidate();
}
}
[Category("Appearance")]
[DefaultValue(32)]
publicint ImageHeight
{
get { return _imageHeight; }
set
{
_imageHeight = value;
Invalidate();
}
}
[Category("Appearance")]
[DefaultValue(5)]
publicint ImageTextSpacing
{
get { return _imageTextSpacing; }
set
{
_imageTextSpacing = value;
Invalidate();
}
}
[Category("Appearance")]
[Description("Determines the alignment of the image within the control.")]
[DefaultValue(ContentAlignment.MiddleLeft)]
public ContentAlignment ImageAlign
{
get { return _imageAlign; }
set
{
_imageAlign = value;
Invalidate();
}
}
#endregion
#region Events
[Category("Property Changed")]
[Description("Occurs when the Image property value changes.")]
publicevent EventHandler ImageChanged;
protectedvirtualvoidOnImageChanged(EventArgs e)
{
ImageChanged?.Invoke(this, e);
}
#endregion
#region Overridden Methods
protectedoverridevoidOnPaint(PaintEventArgs e)
{
// 计算图片矩形(根据 ImageAlign 对齐)
Rectangle imageRect = GetImageRectangle();
// 计算文字矩形(自动避开图片区域)
Rectangle textRect = GetTextRectangle(imageRect);
// 绘制图片
if (Image != null)
{
e.Graphics.DrawImage(Image, imageRect);
}
// 绘制文字
TextFormatFlags flags = TextFormatFlags.WordBreak | TextFormatFlags.VerticalCenter;
// 根据文字对齐方式调整 flags(可选,这里简单使用左对齐)
flags |= TextFormatFlags.Left;
TextRenderer.DrawText(e.Graphics, this.Text, this.Font, textRect, this.ForeColor, flags);
}
#endregion
#region Private Layout Methods
///<summary>
/// 根据 ImageAlign 计算图片的绘制位置
///</summary>
private Rectangle GetImageRectangle()
{
int x = 0, y = 0;
int clientWidth = this.ClientSize.Width;
int clientHeight = this.ClientSize.Height;
// 水平对齐
switch (ImageAlign)
{
case ContentAlignment.TopLeft:
case ContentAlignment.MiddleLeft:
case ContentAlignment.BottomLeft:
x = Padding.Left;
break;
case ContentAlignment.TopCenter:
case ContentAlignment.MiddleCenter:
case ContentAlignment.BottomCenter:
x = (clientWidth - ImageWidth) / 2;
break;
case ContentAlignment.TopRight:
case ContentAlignment.MiddleRight:
case ContentAlignment.BottomRight:
x = clientWidth - Padding.Right - ImageWidth;
break;
}
// 垂直对齐
switch (ImageAlign)
{
case ContentAlignment.TopLeft:
case ContentAlignment.TopCenter:
case ContentAlignment.TopRight:
y = Padding.Top;
break;
case ContentAlignment.MiddleLeft:
case ContentAlignment.MiddleCenter:
case ContentAlignment.MiddleRight:
y = (clientHeight - ImageHeight) / 2;
break;
case ContentAlignment.BottomLeft:
case ContentAlignment.BottomCenter:
case ContentAlignment.BottomRight:
y = clientHeight - Padding.Bottom - ImageHeight;
break;
}
// 边界检查,确保不超出控件范围
x = Math.Max(Padding.Left, Math.Min(x, clientWidth - Padding.Right - ImageWidth));
y = Math.Max(Padding.Top, Math.Min(y, clientHeight - Padding.Bottom - ImageHeight));
returnnew Rectangle(x, y, ImageWidth, ImageHeight);
}
///<summary>
/// 计算文字区域,自动避开图片区域
///</summary>
private Rectangle GetTextRectangle(Rectangle imageRect)
{
Rectangle textRect = new Rectangle(Padding.Left, Padding.Top,
this.ClientSize.Width - Padding.Left - Padding.Right,
this.ClientSize.Height - Padding.Top - Padding.Bottom);
// 如果图片为空,直接返回全区域
if (Image == null) return textRect;
// 根据图片对齐方式,判断文字应该放在图片的哪一侧
// 简单策略:如果图片在左边,文字放在右边;图片在右边,文字放在左边;图片在顶部/底部则文字放在剩余区域
// 更完善的方案可以自由组合,这里演示最常见的几种
bool imageLeft = (ImageAlign == ContentAlignment.MiddleLeft || ImageAlign == ContentAlignment.TopLeft || ImageAlign == ContentAlignment.BottomLeft);
bool imageRight = (ImageAlign == ContentAlignment.MiddleRight || ImageAlign == ContentAlignment.TopRight || ImageAlign == ContentAlignment.BottomRight);
bool imageTop = (ImageAlign == ContentAlignment.TopCenter || ImageAlign == ContentAlignment.TopLeft || ImageAlign == ContentAlignment.TopRight);
bool imageBottom = (ImageAlign == ContentAlignment.BottomCenter || ImageAlign == ContentAlignment.BottomLeft || ImageAlign == ContentAlignment.BottomRight);
if (imageLeft)
{
int textLeft = imageRect.Right + ImageTextSpacing;
textRect = new Rectangle(textLeft, textRect.Y,
this.ClientSize.Width - textLeft - Padding.Right,
textRect.Height);
}
elseif (imageRight)
{
int textRight = imageRect.Left - ImageTextSpacing;
textRect = new Rectangle(Padding.Left, textRect.Y,
Math.Max(0, textRight - Padding.Left),
textRect.Height);
}
elseif (imageTop)
{
int textTop = imageRect.Bottom + ImageTextSpacing;
textRect = new Rectangle(textRect.X, textTop,
textRect.Width,
this.ClientSize.Height - textTop - Padding.Bottom);
}
elseif (imageBottom)
{
int textBottom = imageRect.Top - ImageTextSpacing;
textRect = new Rectangle(textRect.X, Padding.Top,
textRect.Width,
Math.Max(0, textBottom - Padding.Top));
}
else// 居中情况,文字覆盖图片区域(或简单放在下方)
{
// 如果图片居中,文字默认放在图片下方
int textTop = imageRect.Bottom + ImageTextSpacing;
textRect = new Rectangle(textRect.X, textTop,
textRect.Width,
this.ClientSize.Height - textTop - Padding.Bottom);
}
// 确保文字矩形有效
if (textRect.Width < 0) textRect.Width = 0;
if (textRect.Height < 0) textRect.Height = 0;
return textRect;
}
#endregion
#region Double-click to upload image
privatevoidImageLabel_DoubleClick(object sender, EventArgs e)
{
using (OpenFileDialog openFileDialog = new OpenFileDialog())
{
openFileDialog.Title = "请选择一张图片";
openFileDialog.Filter = "图像文件|*.jpg;*.jpeg;*.png;*.gif;*.bmp";
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
this.Image = Image.FromFile(openFileDialog.FileName);
}
}
}
#endregion
}
结束
完整代码如上,欢迎观看,笔者会不定时发布一些实际项目中实用的功能点剥离出来,分享给大家,有需要的帅哥美女可以关注下公众号,赠人玫瑰手有余香,您的支持就是小弟最大的动力
作者:Stephen-kzx
出处:http://www.cnblogs.com/axing/
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