我正在尝试从墨水画布中保存图像，但是保存后它不会创建任何文件，这是我的代码：
RenderTargetBitmap rtb = new RenderTargetBitmap(
(int)canvas.Width, (int)canvas.Height, 0, 0, PixelFormats.Default);
rtb.Render(this.canvas);
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(rtb));
using(var file = new FileStream(@"C:\test.jpg", FileMode.Create))
{
encoder.Save(file);
}
但是，即使我更改目录，它也不会创建任何文件。没有调用异常，也没有显示错误。代码正常运行，没有任何问题，但要生成的文件不存在。
尝试使用保存文件对话框
这是我在 vb.net 中的“添加签名”类中使用的示例代码
单击按钮后会出现一个保存文件对话框，输入文件名并按保存后，它将保存为 png 图像（我使用 pngBitmap 编码器）
这与您使用的格式相同，但添加了保存文件对话框。
顺便提一句。WPFControl.Inkcanvas1 是我的 inkcanvas
'buttonSaveAsClick
'open save file dialog box
Dim sfd As New SaveFileDialog()
sfd.Filter = "Png Files(*.png)|*.png"
'save file as png (render bitmap and convert/save to png)
Dim result As Nullable(Of Boolean) = sfd.ShowDialog()
Dim fileName As String = ""
If result = True Then
fileName = sfd.FileName
Dim size As Size = New Point(750, 400) '= WPFControl.InkCanvas1.RenderSize
Console.WriteLine(WPFControl.InkCanvas1.RenderSize)
Dim rtb As New RenderTargetBitmap(CInt(size.Width), CInt(size.Height), 96, 96, Windows.Media.PixelFormats.Pbgra32)
rtb.Render(WPFControl.InkCanvas1)
Dim png As New PngBitmapEncoder()
png.Frames.Add(BitmapFrame.Create(rtb))
If String.IsNullOrEmpty(fileName) = True Then
MsgBox("Please Enter a File Name", MsgBoxStyle.Exclamation, "File Name required!")
Exit Sub
Else
Console.WriteLine(sfd.FileName)
Console.WriteLine(convertImage.ConvertImageFiletoBytes(sfd.FileName))
End If
Using stm As Stream = File.Create(fileName)
png.Save(stm)
End Using
End If
<Window x:Class="WpfInkCavasSaveImage.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="MainWindow" Height="1091" Width="873" WindowState="Maximized">
<Grid Margin="0,0,0,173" >
<Grid.RowDefinitions>
<RowDefinition Height="1200*" />
<RowDefinition Height="50" />
</Grid.RowDefinitions>
<InkCanvas HorizontalAlignment="Stretch" Margin="1,1,1,10" x:Name="inkCanvas1" VerticalAlignment="Stretch" Width="Auto" RenderTransformOrigin="0.5,0.5" Background="LightGreen" SnapsToDevicePixels="True" IsManipulationEnabled ="True" Grid.RowSpan="2">
<InkCanvas.CacheMode>
<BitmapCache/>
</InkCanvas.CacheMode>
<InkCanvas.DefaultDrawingAttributes>
<DrawingAttributes Color="Black" FitToCurve="True" Height="2.0031496062992127" IgnorePressure="False" IsHighlighter="False" StylusTip="Ellipse" StylusTipTransform="Identity" Width="2.0031496062992127"/>
</InkCanvas.DefaultDrawingAttributes>
</InkCanvas>
<Button x:Name="btnSaveImage" Content="Save Ink Canvas" Height="41" Width="155" Canvas.Left="100" Canvas.Top="900" VerticalAlignment="Top" HorizontalAlignment="Left" RenderTransformOrigin="1.417,14.6" Margin="15,93,0,-84" Background="SkyBlue" Click="btnSaveInkCanvas" Grid.Row="1" BorderBrush="{x:Null}"/>
</Grid>
</Window>
using Microsoft.Win32;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Security.AccessControl;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
namespace WpfInkCavasSaveImage
{
/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
inkCanvas1.Width = System.Windows.SystemParameters.WorkArea.Width;
inkCanvas1.Height = System.Windows.SystemParameters.WorkArea.Height;
}
private void btnSaveInkCanvas(object sender, RoutedEventArgs e)
{
string subpath = Directory.GetCurrentDirectory();
SaveFileDialog saveFileDialog12 = new SaveFileDialog();
saveFileDialog12.Filter = "JPeg Image|*.jpg|Bitmap Image|*.bmp|Gif Image|*.gif|Png File|*.png";
saveFileDialog12.Title = "Save an Image File";
saveFileDialog12.InitialDirectory = subpath;
saveFileDialog12.ShowDialog();
if (saveFileDialog12.FileName == "") return;
subpath = saveFileDialog12.FileName.Substring(0, saveFileDialog12.FileName.Length - saveFileDialog12.SafeFileName.Length);
RenderTargetBitmap rtb = new RenderTargetBitmap((int)inkCanvas1.Width, (int)inkCanvas1.Height, 96d, 96d, PixelFormats.Default);
rtb.Render(inkCanvas1);
DrawingVisual dvInk = new DrawingVisual();
DrawingContext dcInk = dvInk.RenderOpen();
dcInk.DrawRectangle(inkCanvas1.Background, null, new Rect(0d, 0d, inkCanvas1.Width, inkCanvas1.Height));
foreach (System.Windows.Ink.Stroke stroke in inkCanvas1.Strokes)
{
stroke.Draw(dcInk);
}
dcInk.Close();
FileStream fs = File.Open(saveFileDialog12.FileName, FileMode.OpenOrCreate);//save bitmap to file
System.Windows.Media.Imaging.JpegBitmapEncoder encoder1 = new JpegBitmapEncoder();
encoder1.Frames.Add(BitmapFrame.Create(rtb));
encoder1.Save(fs);
fs.Close();
}
}
}
好的，这是我做到的一种方式，这种方式在调试文件夹中导出“test.png”。方法很简单，首先创建一个 InkCanvas 我将其命名ink为本示例的目的。还要创建一个具有 on click 事件处理程序的按钮。在单击事件处理程序上的那个按钮中粘贴这个。
InkCanvasWindow.xaml.cs
Rect bounds = VisualTreeHelper.GetDescendantBounds(ink);
double dpi = 96d;
RenderTargetBitmap rtb = new RenderTargetBitmap((int)bounds.Width, (int)bounds.Height, dpi, dpi, System.Windows.Media.PixelFormats.Default);
DrawingVisual dv = new DrawingVisual();
using (DrawingContext dc = dv.RenderOpen())
{
VisualBrush vb = new VisualBrush(ink);
dc.DrawRectangle(vb, null, new Rect(new Point(), bounds.Size));
}
rtb.Render(dv);
BitmapEncoder pngEncoder = new PngBi tmapEncoder();
pngEncoder.Frames.Add(BitmapFrame.Create(rtb));
using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
{
pngEncoder.Save(ms);
System.IO.File.WriteAllBytes("test.png", ms.ToArray());