使用WorkbookSetting.StreamProvider控制外部资源
可能的使用场景
有时,您的Excel文件包含外部资源,例如链接的图片等。Aspose.Cells允许您使用Workbook.Settings.StreamProvider控制这些外部资源,该方法采用IStreamProvider接口的实现。每当您尝试渲染包含外部资源(例如链接的图片)的工作表时,将调用IStreamProvider接口的方法,从而使您能够针对外部资源采取适当的操作。
使用WorkbookSetting.StreamProvider控制外部资源
以下示例代码说明了Workbook.Settings.StreamProvider的用法。它加载包含链接图像的示例Excel文件。该代码将链接图像替换为Aspose标志,并使用SheetRender类将整个工作表渲染为单个图像。以下屏幕截图显示了示例Excel文件及其渲染输出图像以供参考。正如您所看到的那样,破损的链接图像已被替换为Aspose标志。
示例代码
// For complete examples and data files, please go to https://github.com/aspose-cells/Aspose.Cells-for-.NET | |
class ControlExternalResourcesUsingWorkbookSetting_StreamProvider | |
{ | |
//Source directory | |
static string sourceDir = RunExamples.Get_SourceDirectory(); | |
//Output directory | |
static string outputDir = RunExamples.Get_OutputDirectory(); | |
//Implementation of IStreamProvider | |
class SP : IStreamProvider | |
{ | |
public void CloseStream(StreamProviderOptions options) | |
{ | |
} | |
public void InitStream(StreamProviderOptions options) | |
{ | |
//string sourceDir = RunExamples.Get_SourceDirectory(); | |
//Open the filestream of Aspose Logo and assign it to StreamProviderOptions.Stream property | |
FileStream fi = new FileStream(sourceDir + "sampleControlExternalResourcesUsingWorkbookSetting_StreamProvider.png", FileMode.OpenOrCreate, FileAccess.Read); | |
options.Stream = fi; | |
} | |
} | |
public static void Run() | |
{ | |
//Load sample Excel file containing the external resource e.g. linked image etc. | |
Workbook wb = new Workbook(sourceDir + "sampleControlExternalResourcesUsingWorkbookSetting_StreamProvider.xlsx"); | |
//Provide your implementation of IStreamProvider | |
wb.Settings.ResourceProvider = new SP(); | |
//Access first worksheet | |
Worksheet ws = wb.Worksheets[0]; | |
//Specify image or print options, we need one page per sheet and png output | |
ImageOrPrintOptions opts = new ImageOrPrintOptions(); | |
opts.OnePagePerSheet = true; | |
opts.ImageType = ImageType.Png; | |
//Create sheet render by passing required parameters | |
SheetRender sr = new SheetRender(ws, opts); | |
//Convert your entire worksheet into png image | |
sr.ToImage(0, outputDir + "outputControlExternalResourcesUsingWorkbookSetting_StreamProvider.png"); | |
Console.WriteLine("ControlExternalResourcesUsingWorkbookSetting_StreamProvider executed successfully."); | |
} | |
} |