彩票走势图

Spire.Presentation for .NET 是专业的 PowerPoint组件，开发者可以在 .NET 平台上对 PPT文档进行生成、修改、转换和打印等操作，而无需安装 Microsoft PowerPoint。

本文演示了如何使用Spire.Presentation for .NET在C＃和VB.NET中向PowerPoint文档添加数字签名或删除PowerPoint文档中的现有数字签名。可点击此处下载最新版测试。

添加数字签名

C#

using Spire.Presentation;
using System;
using System.Security.Cryptography.X509Certificates;

namespace AddDigitalSignature
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation ppt = new Presentation();
            //Load a PowerPoint document
            ppt.LoadFromFile("Input.pptx");

            //Add digital signature
            X509Certificate2 x509 = new X509Certificate2("gary.pfx", "e-iceblue");
            ppt.AddDigitalSignature(x509, "e-iceblue", DateTime.Now);

            //Save the result document
            ppt.SaveToFile("AddDigitalSignature.pptx", FileFormat.Pptx2013);
        }
    }
}

VB.NET

Imports Spire.Presentation
Imports System
Imports System.Security.Cryptography.X509Certificates

Namespace AddDigitalSignature
    Class Program
        Private Shared Sub Main(ByVal args As String())
            Dim ppt As Presentation = New Presentation()
            ppt.LoadFromFile("Input.pptx")
            Dim x509 As X509Certificate2 = New X509Certificate2("gary.pfx", "e-iceblue")
            ppt.AddDigitalSignature(x509, "e-iceblue", DateTime.Now)
            ppt.SaveToFile("AddDigitalSignature.pptx", FileFormat.Pptx2013)
        End Sub
    End Class
End Namespace

效果图：

删除数字签名

C#

using Spire.Presentation;
using System;
using System.Security.Cryptography.X509Certificates;

namespace RemoveDigitalSignature
{
    class Program
    {
        static void Main(string[] args)
        {
            //Create a Presentation instance
            Presentation ppt = new Presentation();
            //Load a PowerPoint document 
            ppt.LoadFromFile("AddDigitalSignature.pptx");

            //Detect if the document is digitally signed
            if (ppt.IsDigitallySigned == true)
            {
                //Remove the digital signature
                ppt.RemoveAllDigitalSignatures();
            }

            //Save the result document
            ppt.SaveToFile("RemoveDigitalSignature.pptx", FileFormat.Pptx2013);

        }
    }
}

VB.NET

Imports Spire.Presentation
Imports System
Imports System.Security.Cryptography.X509Certificates

Namespace RemoveDigitalSignature
    Class Program
        Private Shared Sub Main(ByVal args As String())
            Dim ppt As Presentation = New Presentation()
            ppt.LoadFromFile("AddDigitalSignature.pptx")

            If ppt.IsDigitallySigned = True Then
                ppt.RemoveAllDigitalSignatures()
            End If

            ppt.SaveToFile("RemoveDigitalSignature.pptx", FileFormat.Pptx2013)
        End Sub
    End Class
End Namespace

效果图：