从 vb.net 中的文件夹打印图像，每页 8 张图像

Question

i select 使用 vb 的文件夹。net.my 代码如下--

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
    If (FolderBrowserDialog1.ShowDialog() = DialogResult.OK) Then
        TextBox1.Text = FolderBrowserDialog1.SelectedPath

    End If
End Sub

但问题是我对显示图像一无所知（每页 8 张图像）

Answer 1

VB.Net 版本:

既然你想创建打印预览，我建议你为打印预览创建一个新的Form并跟踪用户输入的PageNumber
```
Dim pageNumber As Integer = 0 'start from 0, but change this according to the user input accordingly
```

您可以使用 System.IO

中的 Directory.GetFiles 从给定文件夹中获取文件列表

Dim rawpaths As List(Of String) = Directory.GetFiles(folder).ToList() 'This gets all files, not only images

您可能需要根据 this 提供可接受的图像扩展列表。

Dim validImageFormat As New List(Of String) From {"jpg", "bmp", "png", "jpeg", "gif", "tiff"}

并过滤您的文件结果，使它们只包含像这样的可接受的图像结果（使用 Split 方法，Contains，等等...）

Dim paths As List(Of String) = New List(Of String)
For Each rawpath As String In rawpaths
    Dim rawwords As String() = rawpath.Split(".") 'split the rawpath, the important is the last element, which is the file extension
    If (validImageFormat.Contains(rawwords(rawwords.Length - 1))) Then 'the rawpath is a valid image path
        paths.Add(rawpath) 'this is a valid image path
    End If
Next

然后，在您的打印预览中 Form 您可能需要列出您的 8 个 ListBox 以便您稍后控制显示以及处理以下情况图片数量不是8的乘积

Dim pbList As List(Of PictureBox) = New List(Of PictureBox)
Private Sub printPreviewForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    pbList.Add(PictureBox1) 'list your picture box will help you later
    pbList.Add(PictureBox2)
    pbList.Add(PictureBox3)
    pbList.Add(PictureBox4)
    pbList.Add(PictureBox5)
    pbList.Add(PictureBox6)
    pbList.Add(PictureBox7)
    pbList.Add(PictureBox8)
End Sub

然后，您需要确定要显示多少张图片（最少1张，最多8张，根据PageNumber）

If (pageNumber * 8 > paths.Count) Then 'exceeds the possible image display
    Return 'this is not allowed, do something
End If
Dim minPathNo As Integer = pageNumber * 8 'get the min and max for later display
Dim maxPathNo As Integer = Math.Min(pageNumber * 8 + 7, paths.Count - 1)

最后，要显示，您可以使用Image.FromFile()方法从您的文件夹中加载图像文件，并使用之前声明的minPathNo和maxPathNo来显示图片安全

If (pageNumber * 8 > paths.Count) Then 'exceeds the possible image display
    Return 'this is not allowed, do something
End If
Dim minPathNo As Integer = pageNumber * 8
Dim maxPathNo As Integer = Math.Min(pageNumber * 8 + 7, paths.Count - 1)
For i As Integer = minPathNo To minPathNo + 7
    Dim pbIndex As Integer = i - minPathNo
    If i <= maxPathNo Then
        pbList(pbIndex).Image = Image.FromFile(paths(i)) 'display existing image
    Else
        pbList(pbIndex).Image = Nothing 'don't display non-existing image
    End If
Next

编辑：

假设您的表单如下所示：

这就是您的代码在一种形式下的样子。在你的情况下，你必须制作两种形式：

Imports System.IO

Public Class Form1
    Dim folder As String = "C:\MyPics"
    Dim validImageFormat As New List(Of String) From {"jpg", "bmp", "png", "jpeg", "gif", "tiff"}
    Dim pbList As List(Of PictureBox) = New List(Of PictureBox)
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim rawpaths As List(Of String) = Directory.GetFiles(folder).ToList() 'Assuming all the file is image
        Dim paths As List(Of String) = New List(Of String)
        For Each rawpath As String In rawpaths
            Dim rawwords As String() = rawpath.Split(".") 'split the rawpath, the important is the last element, which is the file extension
            If (validImageFormat.Contains(rawwords(rawwords.Length - 1))) Then 'the rawpath is a valid image path
                paths.Add(rawpath) 'this is a valid image path
            End If
        Next

        Dim pageNumber As Integer = NumericUpDown1.Value
        If (pageNumber * 8 > paths.Count) Then 'exceeds the possible image display
            Return 'this is not allowed, do something
        End If
        Dim minPathNo As Integer = pageNumber * 8
        Dim maxPathNo As Integer = Math.Min(pageNumber * 8 + 7, paths.Count - 1)
        For i As Integer = minPathNo To maxPathNo
            Dim currentPictureBox As Integer = i - minPathNo
            pbList(currentPictureBox).Image = Image.FromFile(paths(i))
        Next
    End Sub

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        pbList.Add(PictureBox1)
        pbList.Add(PictureBox2)
        pbList.Add(PictureBox3)
        pbList.Add(PictureBox4)
        pbList.Add(PictureBox5)
        pbList.Add(PictureBox6)
        pbList.Add(PictureBox7)
        pbList.Add(PictureBox8)
    End Sub
End Class

您只需更改 numericUpDown（将您的页面模拟为 0、1、2 等...）

从 vb.net 中的文件夹打印图像，每页 8 张图像

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