上传BASE64二进制文件到SharePoint文档库

Question

我一直在寻找上传BASE64二进制文件的方法，我被卡住了。首先一个不知道如何将BASE64二进制文件转换为数组缓冲区，blob，…一切都是关于BASE64字符串，但我有BASE64二进制文件。

你有什么解决办法吗?

Answer 1

您需要将此Base64字符串转换为字节数组。c#编程提供了几种方法来轻松地做到这一点。下面是SharePoint插件和Convert.FromBase64String(String)方法的上传大文件示例，它们都在Microsoft Docs中，最终满足您要求的代码将是这样的:

//This approach is useful for short files, less than 2Mb:
public void UploadFileContentFromBase64(ClientContext ctx, string libraryName, string fileName, string base64Str)
{
Web web = ctx.Web;

// Ensure that target library exists. Create if it is missing.
if (!LibraryExists(ctx, web, libraryName))
{
CreateLibrary(ctx, web, libraryName);
}

FileCreationInformation newFile = new FileCreationInformation();

// The next line of code causes an exception to be thrown for files larger than 2 MB.
newFile.Content = Convert.FromBase64String(base64Str);
newFile.Url = fileName;

// Get instances to the given library.
List docs = web.Lists.GetByTitle(libraryName);

// Add file to the library.
Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(newFile);
ctx.Load(uploadFile);
ctx.ExecuteQuery();
}

//This other approach provides you to Upload large files, more than 2Mb:
public void UploadDocumentContentStreamFromBase64(ClientContext ctx, string libraryName, string fileName, string base64Str)
{
Web web = ctx.Web;
// Ensure that the target library exists. Create it if it is missing.
if (!LibraryExists(ctx, web, libraryName))
{
CreateLibrary(ctx, web, libraryName);
}
byte[] fileContent = Convert.FromBase64String(base64Str);
using (MemoryStream memStream = new MemoryStream(fileContent))
{
FileCreationInformation flciNewFile = new FileCreationInformation();

// This is the key difference for the first case - using ContentStream property
flciNewFile.ContentStream = memStream;
flciNewFile.Url = fileName;
flciNewFile.Overwrite = true;

List docs = web.Lists.GetByTitle(libraryName);
Microsoft.SharePoint.Client.File uploadFile = docs.RootFolder.Files.Add(flciNewFile);

ctx.Load(uploadFile);
ctx.ExecuteQuery();
}
}