ExistingVolumeRequestedEventArgs Class

public class ExistingVolumeRequestedEventArgs : AsyncEventArgs

Public Class ExistingVolumeRequestedEventArgs
   Inherits AsyncEventArgs

public ref class ExistingVolumeRequestedEventArgs : public AsyncEventArgs

Shows how to handle the ExistingVolumeRequested event.

using System;
using ComponentPro.Compression;

...

void HandleOpenVolumeEvents()
{
    // Create a new instance. 
    Zip zip = new Zip();

    zip.SpanningMode = SpanningMode.Spanning;

    // Handle the event. 
    zip.ExistingVolumeRequested += zip_ExistingVolumeRequested;
    
    // Open an existing spanning archive. 
    zip.Open(@"D:\test.zip");            

    // ... 
 
    // Add some files to it. 
    zip.AddFiles(@"c:\my dir");

    // ... 
 
    // Close. 
    zip.Close();
}

void zip_ExistingVolumeRequested(object sender, ExistingVolumeRequestedEventArgs e)
{
    string volumePosition;

    if (e.FirstVolume)
        volumePosition = "the first";
    else if (e.LastVolume)
        volumePosition = "the last";
    else 
        volumePosition = "a middle";

    Console.WriteLine(string.Format("Need {0} volume: {1}", volumePosition, e.VolumeFileName));
    Console.Write("Enter new volume file path or leave blank for default: ");
    string path = Console.ReadLine();

    if (!string.IsNullOrEmpty(path))
        e.VolumeFileName = path;
}

Imports ComponentPro.Compression

...

Private Sub HandleOpenVolumeEvents()
    ' Create a new instance. 
    Dim zip As New Zip()

    zip.SpanningMode = SpanningMode.Spanning

    ' Handle the event. 
    AddHandler zip.ExistingVolumeRequested, AddressOf zip_ExistingVolumeRequested

    ' Open an existing spanning archive. 
    zip.Open("D:\test.zip")

    ' ... 
 
    ' Add some files to it. 
    zip.AddFiles("c:\my dir")

    ' ... 
 
    ' Close. 
    zip.Close()
End Sub 
 
Private Sub zip_ExistingVolumeRequested(ByVal sender As Object, ByVal e As ExistingVolumeRequestedEventArgs)
    Dim volumePosition As String 
 
    If e.FirstVolume Then 
        volumePosition = "the first" 
    ElseIf e.LastVolume Then 
        volumePosition = "the last" 
    Else 
        volumePosition = "a middle" 
    End If 
 
    Console.WriteLine(String.Format("Need {0} volume: {1}", volumePosition, e.VolumeFileName))
    Console.Write("Enter new volume file path or leave blank for default: ")
    Dim path As String = Console.ReadLine()

    If Not String.IsNullOrEmpty(path) Then 
        e.VolumeFileName = path
    End If 
End Sub

Reference