XAML 文件到图像，绑定计算代码隐藏

Question

我有以下代码将 XAML 文件另存为图像流，但未计算绑定。有什么建议吗？

// get byte-array from file
using (var xamlStream = new MemoryStream((byte[])value))
using (var stream = new MemoryStream())
{
var thread = new Thread(() =>
{
// load xaml control from stream
var control = (System.Windows.FrameworkElement)System.Windows.Markup.XamlReader.Load(xamlStream);
if (control == null)
return;
control.DataContext =  new { Person = new { FIRSTNAME = "Test" } };
control.Measure(new System.Windows.Size(double.PositiveInfinity, double.PositiveInfinity));
// get size of control which would be needed by Window
var controlSize = control.DesiredSize;
var rect = new System.Windows.Rect(0, 0, controlSize.Width, controlSize.Height);
// render XAML to bitmap
var targetBitmap = new RenderTargetBitmap((int)controlSize.Width, (int)controlSize.Height, 120, 96, PixelFormats.Pbgra32);
control.Arrange(rect);
targetBitmap.Render(control);
// convert to png and save to sream
var png = new PngBitmapEncoder();
png.Frames.Add(BitmapFrame.Create(targetBitmap));
png.Save(stream);
});
thread.SetApartmentState(ApartmentState.STA); //Set the thread to STA
thread.Start();
thread.Join();
}

XAML 代码：

<Canvas  
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
x:Name="_PrintCanvas" Width="1585" Height="1000">
<TextBlock FontSize="80" Foreground="Red"  Text="{Binding Person.FIRSTNAME}" Canvas.Top="800" Canvas.Left="70" Margin="0,0,0,0"/>
</Canvas>

有没有办法显式计算代码隐藏中的绑定？

Answer 1

所以我得到了解决方案：在targetBitmap.Render(control);之前有一个缺失的UpdateLayout()

因此，新代码如下所示：

// get byte-array from file
using (var xamlStream = new MemoryStream((byte[])value))
using (var stream = new MemoryStream())
{
var dataContext = new DataPackageController();
dataContext.SetData(context);
var thread = new Thread(() =>
{
// load xaml control from stream
var control = (System.Windows.Controls.Canvas)System.Windows.Markup.XamlReader.Load(xamlStream);
if (control == null)
return;
control.DataContext = new { Person = new { FIRSTNAME = "Test" } };
control.Measure(new System.Windows.Size(double.PositiveInfinity, double.PositiveInfinity));
// get size of control which would be needed by Window
var controlSize = control.DesiredSize;
var rect = new System.Windows.Rect(0, 0, controlSize.Width, controlSize.Height);
// render XAML to bitmap
var targetBitmap = new RenderTargetBitmap((int)controlSize.Width, (int)controlSize.Height, 120, 96, PixelFormats.Pbgra32);
control.Arrange(rect);
control.InvalidateVisual();
control.UpdateLayout();
targetBitmap.Render(control);
// convert to png and save to sream
var png = new PngBitmapEncoder();
png.Frames.Add(BitmapFrame.Create(targetBitmap));
png.Save(stream);
});
thread.SetApartmentState(ApartmentState.STA); //Set the thread to STA
thread.Start();
thread.Join();
}