itext7 html to pdf - vb example please?

Question

Please can someone provide me with a simple example of converting a file from HTML to PDF in VB? I can find Java and C# examples but nothing using VB.

Unless the C# is doing something interesting, it should translate directly to VB. I'd suggest that you try translating a C# example and update your question with any details that cause problems. — Craig, Sep 21 '22 at 16:32

Tu deschizi eu inchid · Answer 1 · 2022-09-22T19:41:58.157

The following shows how to use NuGet packages iText7 and itext7.pdfhtml to convert HTML to a PDF file.

VS 2022:

Open Visual Studio 2022
Click
Click File
Select New
Select Project
For filter, select:
Click Next
Enter desired project name (ex: ConvertHtmlToPdfTest)
Select desired .NET Framework (ex: .NET Framework 4.8)
Click Create

Open Toolbox:

In VS menu, click View
Select Toolbox

Open Solution Explorer:

In VS menu, click View
Select Solution Explorer

Open Properties Window

In VS menu, click View
Select Properties Window

Set Default package management format (optional)

In VS menu, click Tools
Select Options...
Expand NuGet Package Manager
Select General
Under "Package Management", set Default package management format to PackageReference
Click OK

Download/install NuGet package (iText7):

In Solution Explorer, right-click <project name> (ex: ConvertHtmlToPdfTest)
Select Manage NuGet Packages...
Click Browse tab
In the search box type: iText7
Select iText7
Select desired version (ex: 7.2.3)
Click Install
If a MessageBox appears, click OK

Download/install NuGet package (iText7.pdfhtml):

In Solution Explorer, right-click <project name> (ex: ConvertHtmlToPdfTest)
Select Manage NuGet Packages...
Click Browse tab
In the search box type: iText7.pdfhtml
Select iText7.pdfhtml
Select desired version (ex: 4.0.3)
Click Install
If a MessageBox appears, click OK

Add a module: (name: HelperiText7.vb)

In VS menu, click Project
Select Add New Item...
Select Module (name: HelperiText7.vb)
Click Add

HelperiText7.vb:

Imports System.IO
Imports iText.Html2pdf

Module HelperiText7
    Public Sub CreatePdf(htmlFilename As String, pdfFilename As String, Optional baseUri As String = Nothing)
        Dim pdfData As Byte() = Nothing

        If Not File.Exists(htmlFilename) Then
            Throw New Exception($"Error: '{htmlFilename}' doesn't exist.")
        End If

        Using fs As FileStream = New FileStream(htmlFilename, FileMode.Open, FileAccess.Read)
            Using ms As MemoryStream = New MemoryStream()
                'when specifying HTML as a string And the HTML includes
                'a resource that uses relative paths,
                'it's necessary to specify the baseUri (path)

                'create new instance
                Dim properties As ConverterProperties = New ConverterProperties()

                If Not String.IsNullOrEmpty(baseUri) Then
                    'set value
                    properties.SetBaseUri(baseUri)
                Else
                    'get folder name that HTML file exists in
                    Dim folderName As String = Path.GetDirectoryName(htmlFilename)

                    'set value
                    properties.SetBaseUri(folderName)
                End If

                'Debug.WriteLine($"BaseURI: {properties.GetBaseUri()}")

                'convert HTML to PDF
                HtmlConverter.ConvertToPdf(fs, ms, properties)

                'save to Byte()
                pdfData = ms.ToArray()
            End Using

            'save to PDF file
            File.WriteAllBytes(pdfFilename, pdfData)
        End Using
    End Sub

    Public Sub CreatePdfFromHtmlString(htmlString As String, pdfFilename As String, baseUri As String)
        Dim pdfData As Byte() = Nothing

        Using ms As MemoryStream = New MemoryStream()
            'when specifying HTML as a string And the HTML includes
            'a resource that uses relative paths,
            'it's necessary to specify the baseUri (path)

            'create new instance
            Dim properties As ConverterProperties = New ConverterProperties()

            'set value
            properties.SetBaseUri(baseUri)

            'convert HTML to PDF
            HtmlConverter.ConvertToPdf(htmlString, ms, properties)

            'save to Byte()
            pdfData = ms.ToArray()
        End Using

        'save to PDF file
        File.WriteAllBytes(pdfFilename, pdfData)
    End Sub
End Module

For testing, I used the following:

test.html

<!DOCTYPE html>

<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
    <meta charset="utf-8" />
    <title></title>
</head>
<body>
    <h2>HTML Test</h2>

    <div>
        <IMG src="./images/strawberry.jpg" ALT="strawberry">
    </div>

    <p>
        <div>
            This is a test message
        </div>
</body>
</html>

Note: In the HTML above, the image uses a relative path.

File/Folder structure:

images\strawberry.jpg:

The following demonstrates converting test.html to a PDF file.

Using ofd As OpenFileDialog = New OpenFileDialog()
    ofd.Filter = "HTML File (*.html)|*.html"
    ofd.Title = "Select HTML Filename"

    If ofd.ShowDialog() = DialogResult.OK Then
        Using sfd As SaveFileDialog = New SaveFileDialog()
            sfd.Filter = "PDF File (*.pdf)|*.pdf"
            sfd.Title = "Select PDF Filename To Save As"
            If sfd.ShowDialog() = DialogResult.OK Then
                'the image in the HTML uses a relative path
                'set baseUri = to the folder that contains the HTML file
                Dim baseUri As String = Path.GetDirectoryName(ofd.FileName)
                Debug.WriteLine($"baseUri: {baseUri}")

                'convert HTML to PDF
                HelperiText7.CreatePdf(ofd.FileName, sfd.FileName, baseUri)
            End If
        End Using
    End If
End Using

Resources:

Additional Resources:

itext7 html to pdf - vb example please?

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