在 c#, windows 窗体中，我想根据输入的双精度值更改按钮背景颜色，该值介于 1 和 100 之间。例如
【问题讨论】：
标签： c# windows winforms button background-color
您可以创建一个自定义按钮控件并使用它的 BackgroundImage 来绘制进度。这样你就可以保持按钮的外观和感觉（包括视觉风格）。所有的绘画逻辑都在控件中，应用代码如下：
private void numericUpDown1_ValueChanged(object sender, EventArgs e)
{
percentButton1.Percent = (int)numericUpDown1.Value;
percentButton1.Text = $"{ percentButton1.Percent}%";
}
这是你看到的结果：
在以下示例中，我为 PercentButton 创建了 3 个属性：
代码如下：
using System.ComponentModel;
using System.Drawing;
using System.Windows.Forms;
public class PercentButton : Button
{
public PercentButton()
{
BackgroundImageLayout = ImageLayout.Stretch;
}
Color percentCompletedColor = Color.Yellow;
[DefaultValue(typeof(Color), "Yellow")]
public Color PercentCompletedColor
{
get { return percentCompletedColor; }
set
{
if (percentCompletedColor != value)
{
percentCompletedColor = value;
Invalidate();
}
}
}
Color percentRemainingColor = Color.Blue;
[DefaultValue(typeof(Color), "Blue")]
public Color PercentRemainingColor
{
get { return percentRemainingColor; }
set
{
if (percentRemainingColor != value)
{
percentCompletedColor = value;
Invalidate();
}
}
}
private int percent = 50;
[DefaultValue(50)]
public int Percent
{
get { return percent; }
set
{
if (value < 0) value = 0;
if (value > 100) value = 100;
if (percent != value)
{
percent = value;
Invalidate();
}
}
}
[Browsable(false)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public override Image BackgroundImage
{
get { return base.BackgroundImage; }
set { base.BackgroundImage = value; }
}
[Browsable(false)]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
public override ImageLayout BackgroundImageLayout
{
get { return base.BackgroundImageLayout; }
set { base.BackgroundImageLayout = value; }
}
protected override void OnPaint(PaintEventArgs pevent)
{
if (BackgroundImage == null)
BackgroundImage = new Bitmap(100, 10);
using (var g = Graphics.FromImage(BackgroundImage))
{
if (Percent > 0)
using (var b1 = new SolidBrush(PercentCompletedColor))
g.FillRectangle(b1, new Rectangle(0, 0, Percent, 10));
if (Percent < 100)
using (var b1 = new SolidBrush(PercentRemainingColor))
g.FillRectangle(b1, new Rectangle(Percent, 0, Percent, 10));
}
base.OnPaint(pevent);
}
}
【讨论】：
value 是否等于已分配的值来防止对Invalidate 的不必要调用。比如set { if (value != percentRemainingColor) { percentRemainingColor = value; Invalidate(); } }等。这对于Percent属性来说可能是最重要的。正如所写，我可以一遍又一遍地为其分配相同的值，然后Invalidate 将被调用。
您不能使用 BackgroundColor 属性同时拥有具有两种颜色的按钮。 首先，您必须创建一个组件按钮并自定义。 右键单击>添加新项目>从Windows窗体中选择CustomControl>输入名称>确定
之后，编辑代码就足够了。该类继承自按钮类而不是控件类
public partial class TwoColorButton : Button
{
Color clr1, clr2;
private Color color1 = Color.DodgerBlue;
private Color color2 = Color.MidnightBlue;
private int angle = 90;
private int textX = 100;
private int textY = 25;
private String text = "";
public int ButtonAngle
{
get { return angle; }
set { angle = value; Invalidate(); }
}
public String ButtonText
{
get { return text; }
set { text = value; Invalidate(); }
}
public Color StartColor
{
get { return color1; }
set { color1 = value; Invalidate(); }
}
public Color EndColor
{
get { return color2; }
set { color2 = value; Invalidate(); }
}
public int GradientAngle
{
get { return angle; }
set { angle = value; Invalidate(); }
}
public int TextLocation_X
{
get { return textX; }
set { textX = value; Invalidate(); }
}
public int TextLocation_Y
{
get { return textY; }
set { textY = value; Invalidate(); }
}
public TwoColorButton()
{
this.Size = new Size(100, 40);
this.BackColor = Color.Transparent;
this.FlatStyle = FlatStyle.Flat;
this.FlatAppearance.BorderSize = 0;
this.FlatAppearance.MouseOverBackColor = Color.Transparent;
this.FlatAppearance.MouseDownBackColor = Color.Transparent;
text = this.Text;
}
protected override void OnLostFocus(EventArgs e)
{
base.OnLostFocus(e);
color1 = clr1;
color2 = clr2;
this.Invalidate();
}
protected override void OnResize(EventArgs e)
{
base.OnResize(e);
textX = (int)((this.Width / 3) - 1);
textY = (int)((this.Height / 3) + 5);
}
//draw circular button function
//draw rectangular button function
void DrawRectangularButton(Graphics g)
{
Color c1 = Color.FromArgb(250, color1);
Color c2 = Color.FromArgb(250, color2);
Brush b = new System.Drawing.Drawing2D.LinearGradientBrush(ClientRectangle, c1, c2, angle);
g.FillRectangle(b, 0, 0, this.Width, this.Height);
for (int i = 0; i < 2; i++)
{
g.DrawLine(new Pen(new SolidBrush(Color.FromArgb(220, 220, 220))), this.Width - i, 0, this.Width - i, this.Height);
g.DrawLine(new Pen(new SolidBrush(Color.FromArgb(220, 220, 220))), 0, this.Height - i, this.Width, this.Height - i);
g.DrawLine(new Pen(new SolidBrush(Color.FromArgb(220, 220, 220))), 0 + i, 0, 0 + i, this.Height);
g.DrawLine(new Pen(new SolidBrush(Color.FromArgb(220, 220, 220))), 0, 0 + i, this.Width, i);
}
Point p = new Point(textX, textY);
SolidBrush frcolor = new SolidBrush(this.ForeColor);
g.DrawString(text, this.Font, frcolor, p);
b.Dispose();
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
this.DrawRectangularButton(e.Graphics);
}
}
【讨论】：