Silverlight 打印
摘自：http://www.cnblogs.com/jiajiayuan/archive/2012/04/13/2444246.html
Silverlight中的打印只有一个类，那就是PrintDocment这个对象来实现。
下面我用两种方法来实现Silverlight的打印：
第一种：
private void btnPrint_Click(object sender, RoutedEventArgs e)
{
PrintDocument document = new PrintDocument();
// tell the API what to print
document.PrintPage += (s, args) =>
{
args.PageVisual = GPrint;
};
// call the Print() with a proper name which will be visible in the Print Queue
document.Print("Silverlight Print Application Demo");
}
第二种：
实现方式也很简单，其实只需两个步骤即可完成，即绑定PrintDocument的PrintPage事件和调用Print方法。
PrintDocument document = new PrintDocument();
document.PrintPage += documentImage_PrintPage;
document.Print("Image Document");
这个就完成了一个打印，其中PrintPage事件是最为重要的，因为整个打印的工作都是在这个事件中完成的，另外该事件的参数 PrintPageEventArgs构成了整个打印过程中的属性的设置；Print方法需要传递一个参数，参数为打印的文件的名称，在调用该方法的时候 开始触发一系列的打印事件。
PrintPageEventArgs类型的属性:
PrintableArea：获取一个Size类型的值，表示打印的范围，分别表示Height和Width，如果打印的部分超出了区域，则被截取。
PageMargins：获取打印页的Margin值。
PageVisual：设置要打印的对象,可以是一个TextBlock、Image，也可以是一个复杂的元素(Grid或者Canvas)。
HasMorePages：一个bool值，标识是否多页。
一个简单的例子:
private void btnPrintImage_Click(object sender, RoutedEventArgs e)
{
PrintDocument document = new PrintDocument();
document.PrintPage += new EventHandler<PrintPageEventArgs>(document_PrintPage);
document.Print("Print Image");
}
void document_PrintPage(object sender, PrintPageEventArgs e)
{
Image imagePrint = new Image();
imagePrint.Source = img.Source;
imagePrint.Height = e.PrintableArea.Height;
imagePrint.Width = e.PrintableArea.Width;
e.PageVisual = imagePrint;
e.HasMorePages = false;
}
分页打印的例子：
//当前打印的行的索引，用于遍历ListBox.Items
private int listPrintIndex;
private void btnPrintList_Click(object sender, RoutedEventArgs e)
{
//初始值为0
listPrintIndex = 0;
PrintDocument document = new PrintDocument();
document.PrintPage += new EventHandler<PrintPageEventArgs>(document_PrintPage);
document.Print("Print List");
}
//设置每一项之间的间距
private int extraMargin = 50;
void document_PrintPage(object sender, PrintPageEventArgs e)
{
//定义一个打印的元素
Canvas printSurface = new Canvas();
e.PageVisual = printSurface;
//得到最顶端位置
double topPosition = e.PageMargins.Top + extraMargin;
//遍历当前的ListBox.Items
while (listPrintIndex<lstPrint.Items.Count)
{
//实例化TextBlock用来存放ListItem的值
TextBlock txt = new TextBlock();
txt.FontSize = 30;
//得到ListBox每一项的值
txt.Text = lstPrint.Items[listPrintIndex].ToString();
double measuredHeight = txt.ActualHeight;
//如果打印的当前行高度不合适的话，则进行分页
if (measuredHeight>(e.PrintableArea.Height- topPosition- extraMargin))
{
e.HasMorePages = true;
return ;
}
//设置TextBlock在Canvas中的位置
txt.SetValue(Canvas.TopProperty, topPosition);
txt.SetValue(Canvas.LeftProperty, e.PageMargins.Left + extraMargin);
//将TextBlock添加到打印的元素中去
printSurface.Children.Add(txt);
listPrintIndex++;
//追加高度
topPosition = topPosition + measuredHeight;
}
e.HasMorePages = false;
}
有时我们会发现打印的图片并不完整，这样就需要一个类：
public static class Extensions
{
public static void Print(this FrameworkElement element,
string Document, HorizontalAlignment HorizontalAlignment,
VerticalAlignment VerticalAlignment, Thickness PageMargin,
bool PrintLandscape, bool ShrinkToFit, Action OnPrintComplete)
{
Print(new List<FrameworkElement>() { element }, Document,
HorizontalAlignment, VerticalAlignment, PageMargin,
PrintLandscape, ShrinkToFit, OnPrintComplete);
}
public static void Print<T>(this List<T> elements,
string Document, HorizontalAlignment HorizontalAlignment,
VerticalAlignment VerticalAlignment, Thickness PageMargin,
bool PrintLandscape, bool ShrinkToFit, Action OnPrintComplete)
{
PrintDocument printDocument = new PrintDocument();
PageMargin = PageMargin == null ? new Thickness(10) : PageMargin;
Document = (string.IsNullOrEmpty(Document)) ? "Print Document" : Document;
int currentItemIndex = 0;
printDocument.PrintPage += (s, e) =>
{
if (!typeof(FrameworkElement).IsAssignableFrom(elements[currentItemIndex].GetType()))
{
throw new Exception("Element must be an " +"object inheriting from FrameworkElement");
}
FrameworkElement element = elements[currentItemIndex] as FrameworkElement;
if (element.Parent == null || element.ActualWidth == double.NaN ||element.ActualHeight == double.NaN)
{
throw new Exception("Element must be rendered, " +
"and must have a parent in order to print.");
}
TransformGroup transformGroup = new TransformGroup();
//First move to middle of page... 首先移动到页面的中间
transformGroup.Children.Add(new TranslateTransform() //TranslateTransform偏移动画
{
X = (e.PrintableArea.Width - element.ActualWidth) / 2,
Y = (e.PrintableArea.Height - element.ActualHeight) / 8
});
double scale = 1;
if (PrintLandscape) //如果打印空白 需要旋转
{
//Then, rotate around the center 然后旋转到中心
transformGroup.Children.Add(new RotateTransform()
{
Angle = 90,
CenterX = e.PrintableArea.Width / 2,
CenterY = e.PrintableArea.Height / 2
});
if (ShrinkToFit) //如果自适应大小
{
if ((element.ActualWidth + PageMargin.Left +PageMargin.Right) > e.PrintableArea.Height) //如果宽度大于纸张的高度
{
//Math.Round 方法 将值舍入到最接近的整数或指定的小数位数。
scale = Math.Round(e.PrintableArea.Height /(element.ActualWidth + PageMargin.Left + PageMargin.Right), 2);
}
if ((element.ActualHeight + PageMargin.Top + PageMargin.Bottom) > e.PrintableArea.Width) //如果高度大于纸张的宽度
{
double scale2 = Math.Round(e.PrintableArea.Width /(element.ActualHeight + PageMargin.Top + PageMargin.Bottom), 2);
scale = (scale2 < scale) ? scale2 : scale;
}
}
}
else if (ShrinkToFit) //如果不打印空白并自适应大小 不需要旋转
{
//Scale down to fit the page + margin
if ((element.ActualWidth + PageMargin.Left + PageMargin.Right) > e.PrintableArea.Width) //如果宽度大于纸张的宽度
{
scale = Math.Round(e.PrintableArea.Width /(element.ActualWidth + PageMargin.Left + PageMargin.Right), 2);
}
if ((element.ActualHeight + PageMargin.Top + PageMargin.Bottom) > e.PrintableArea.Height) //如果高度大于纸张的高度
{
double scale2 = Math.Round(e.PrintableArea.Height /(element.ActualHeight + PageMargin.Top + PageMargin.Bottom), 2);
scale = (scale2 < scale) ? scale2 : scale;
}
}
//Scale down to fit the page + margin
if (scale != 1)
{
transformGroup.Children.Add(new ScaleTransform() //ScaleTransform缩放动画
{
ScaleX = scale,
ScaleY = scale,
CenterX = e.PrintableArea.Width / 2,
CenterY = e.PrintableArea.Height / 2
});
}
if (VerticalAlignment == VerticalAlignment.Top)
{
//Now move to Top
if (PrintLandscape)
{
transformGroup.Children.Add(new TranslateTransform()
{
X = 0,
Y = PageMargin.Top - (e.PrintableArea.Height -(element.ActualWidth * scale)) / 2
});
}
else
{
transformGroup.Children.Add(new TranslateTransform()
{
X = 0,
Y = PageMargin.Top - (e.PrintableArea.Height -(element.ActualHeight * scale)) / 2
});
}
}
else if (VerticalAlignment == VerticalAlignment.Bottom)
{
//Now move to Bottom
if (PrintLandscape)
{
transformGroup.Children.Add(new TranslateTransform()
{
X = 0,
Y = ((e.PrintableArea.Height -(element.ActualWidth * scale)) / 2) - PageMargin.Bottom
});
}
else
{
transformGroup.Children.Add(new TranslateTransform()
{
X = 0,
Y = ((e.PrintableArea.Height -(element.ActualHeight * scale)) / 2) - PageMargin.Bottom
});
}
}
if (HorizontalAlignment == HorizontalAlignment.Left)
{
//Now move to Left
if (PrintLandscape)
{
transformGroup.Children.Add(new TranslateTransform()
{
X = PageMargin.Left - (e.PrintableArea.Width -(element.ActualHeight * scale)) / 2,
Y = 0
});
}
else
{
transformGroup.Children.Add(new TranslateTransform()
{
X = PageMargin.Left - (e.PrintableArea.Width -(element.ActualWidth * scale)) / 2,
Y = 0
});
}
}
else if (HorizontalAlignment == HorizontalAlignment.Right)
{
//Now move to Right
if (PrintLandscape)
{
transformGroup.Children.Add(new TranslateTransform()
{
X = ((e.PrintableArea.Width -(element.ActualHeight * scale)) / 2) - PageMargin.Right,
Y = 0
});
}
else
{
transformGroup.Children.Add(new TranslateTransform()
{
X = ((e.PrintableArea.Width -(element.ActualWidth * scale)) / 2) - PageMargin.Right,
Y = 0
});
}
}
e.PageVisual = element;
e.PageVisual.RenderTransform = transformGroup;
//Increment to next item,
currentItemIndex++;
//If the currentItemIndex is less than the number of elements, keep printing
e.HasMorePages = currentItemIndex < elements.Count;
};
printDocument.EndPrint += delegate(object sender, EndPrintEventArgs e)
{
foreach (var item in elements)
{
FrameworkElement element = item as FrameworkElement;
//Reset everything...
TransformGroup transformGroup = new TransformGroup();
transformGroup.Children.Add(new ScaleTransform() { ScaleX = 1, ScaleY = 1 }); //缩放动画
transformGroup.Children.Add(new RotateTransform() { Angle = 0 }); //旋转动画
transformGroup.Children.Add(new TranslateTransform() { X = 0, Y = 0 }); //偏移动画
element.RenderTransform = transformGroup;
}
//Callback to complete
if (OnPrintComplete != null)
{
OnPrintComplete();
}
};
printDocument.Print(Document);
}
}
调用这个类：
private void btnPrint_Click(object sender, RoutedEventArgs e)
{
Extensions.Print(GPrint, "MyPrint",
HorizontalAlignment.Center, VerticalAlignment.Top,
new Thickness(10, 0, 10, 0), true, true, null);
}
这样就能完整的打印了，不过打印出来的效果可能是横向的。
