我有一个png图像有透明的部分，如何设置这个png图像像我的WinForms表单的背景图像，而不是失去透明度？我用C＃。谢谢！
答案 0 :(得分：0)
这里我写了一个用于绘制表单的代码。您可以根据我们的要求更改颜色和透明度。我用颜色作为表格的背景。您可以根据您的要求将其更改为图片。这是一个示例代码。
首先，您需要创建一个包含这些函数的静态类
public enum FormType
{
MDI,
Child
}
public static void PaintFrom(Form frm, PaintEventArgs e, FormType formType)
{
if (formType == FormType.MDI)
{
Graphics mGraphics = e.Graphics;
Pen pen1 = new Pen(Color.FromArgb(96, 155, 173), 1);
Rectangle Area1 = new Rectangle(0, 0, frm.Width - 1, frm.Height - 1);
LinearGradientBrush LGB = new LinearGradientBrush(Area1, Color.FromArgb(96, 155, 173), Color.FromArgb(245, 251, 251), LinearGradientMode.Vertical);
mGraphics.FillRectangle(LGB, Area1);
mGraphics.DrawRectangle(pen1, Area1);
PictureBox picBox = new PictureBox();
Color backColor = Color.Transparent;
Bitmap bm = new Bitmap(ImagePath + "title_bar.png");
//frm.Controls.Add(picBox);
Point pt = new Point(0, 0);
picBox.Location = pt;
picBox.Image = bm;
picBox.Width = frm.Width - 1;
picBox.Height = 24;//frm.Height - 1;
picBox.BackColor = backColor;
picBox.BackgroundImageLayout = ImageLayout.Stretch;
PictureBox closeBox = new PictureBox();
//frm.Controls.Add(closeBox);
bm = new Bitmap(ImagePath + "close.gif");
pt = new Point(frm.Width - (bm.Width), -1);
closeBox.Location = pt;
closeBox.Image = bm;
closeBox.Width = bm.Width + 1;
closeBox.Height = bm.Width + 1;
closeBox.BackColor = backColor;
closeBox.BackgroundImageLayout = ImageLayout.Stretch;
PictureBox minBox = new PictureBox();
//frm.Controls.Add(closeBox);
bm = new Bitmap(ImagePath + "close.gif");
pt = new Point(frm.Width - (2*(bm.Width))-1, bm.Width);
minBox.Location = pt;
minBox.Image = bm;
minBox.Width = bm.Width + 1;
minBox.Height = bm.Width + 1;
minBox.BackColor = backColor;
minBox.BackgroundImageLayout = ImageLayout.Stretch;
frm.Controls.Add(picBox);
picBox.Controls.Add(closeBox);
picBox.Controls.Add(minBox);
minBox.Click+=new EventHandler(minBox_Click);
closeBox.Click += new EventHandler(closeBox_Click);
}
else
{
PaintForm(frm, e);
}
}
public static void PaintForm(Form frm, PaintEventArgs e)
{
Graphics mGraphics = e.Graphics;
Pen pen1 = new Pen(Color.FromArgb(96, 155, 173), 1);
Rectangle Area1 = new Rectangle(0, 0, frm.Width - 1, frm.Height - 1);
LinearGradientBrush LGB = new LinearGradientBrush(Area1, Color.FromArgb(96, 155, 173), Color.FromArgb(245, 251, 251), LinearGradientMode.Vertical);
mGraphics.FillRectangle(LGB, Area1);
mGraphics.DrawRectangle(pen1, Area1);
PictureBox picBox=new PictureBox();
Color backColor = Color.Transparent;
Bitmap bm=new Bitmap(ImagePath+"title_bar.png");
//frm.Controls.Add(picBox);
Point pt=new Point(0,0);
picBox.Location = pt;
picBox.Image = bm;
picBox.Width = frm.Width - 1;
picBox.Height = 24;//frm.Height - 1;
picBox.BackColor = backColor;
picBox.BackgroundImageLayout = ImageLayout.Stretch;
PictureBox closeBox = new PictureBox();
//frm.Controls.Add(closeBox);
bm = new Bitmap(ImagePath + "close.gif");
pt = new Point(frm.Width - (bm.Width), -1);
closeBox.Location = pt;
closeBox.Image = bm;
closeBox.Width = bm.Width + 1;
closeBox.Height = bm.Width + 1;
closeBox.BackColor = backColor;
closeBox.BackgroundImageLayout = ImageLayout.Stretch;
foreach (Control ctr in frm.Controls)
{
if (ctr.HasChildren)
{
if (ctr is DataGridView)
{
DataGridView dtg = ctr as DataGridView;
DataGridViewCellStyle dtstyle=new DataGridViewCellStyle();
dtstyle.BackColor = Color.FromArgb(96, 155, 173);
dtg.ColumnHeadersDefaultCellStyle = dtstyle;
}
else if (ctr is TextBox)
{
}
else if (ctr is TabControl)
{
}
else
{
ctr.BackColor = backColor;
}
}
if (ctr is Label)
{
ctr.BackColor = backColor;
}
}
frm.Controls.Add(picBox);
picBox.Controls.Add(closeBox);
closeBox.Click+=new EventHandler(closeBox_Click);
}
static void closeBox_Click(object sender, EventArgs e)
{
PictureBox close = sender as PictureBox;
PictureBox pic = close.Parent as PictureBox;
Form fm = pic.Parent as Form;
fm.Close();
}
static void minBox_Click(object sender, EventArgs e)
{
PictureBox min = sender as PictureBox;
PictureBox pic = min.Parent as PictureBox;
Form fm = pic.Parent as Form;
fm.WindowState = FormWindowState.Minimized;
}
然后你需要为表单调用一个Paint事件，在这种情况下你可以像这样绘制表单
private void frmComplaints_Paint(object sender, PaintEventArgs e)
{
UI.Common.PaintForm(this, e);
}
我为这个函数使用了一个静态类UI.Common，我使用了一个标题栏的图像。在您的情况下，您可以使用png图像作为背景。代码中的ImagePath是一个常量变量，您可以在其中设置保存图像的目录的路径