CS0012 C# The type 'HttpContext' is defined in an assembly that is not referenced

Question

I have this code to Merge documents to .PDF using Spire but i get the following code in this line result.Save(outputFile,Spire.Pdf.FileFormat.PDF);

CS0012 C# The type 'HttpContext' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.

I tried to add this Assembly code to App.config file but no luck.

<assemblies>
        <add assembly="MyAssembly" Version="4.0.0.0" Culture="neutral" PublicKeyToken="b03f5f7f11d50a3a"/>

Here is the code below

private void button1_Click(object sender, EventArgs e)
        {

            OpenFileDialog ofd = new OpenFileDialog();

            ofd.Filter = "All files (*.docx, *.pdf, *.pptx, *.pdf)| *.docx; *.pdf; *.pptx; *.xlsx";

            ofd.Multiselect = true;

            if (DialogResult.OK == ofd.ShowDialog())
            {

                string[] files = ofd.FileNames;

                listBox1.Items.AddRange(files);
            }

    }

        private void button2_Click(object sender, EventArgs e)
        {
            string ext = string.Empty;
            List<Stream> filesStreams = new List<Stream>();
            MemoryStream ms1 = new MemoryStream();
            MemoryStream ms2 = new MemoryStream();
            MemoryStream ms3 = new MemoryStream();
            foreach (object item in listBox1.Items)
            {
                ext = Path.GetExtension(item.ToString());
                switch (ext)
                {
                    case ".docx":
                        Document doc = new Document(item.ToString());
                        doc.SaveToStream(ms1, Spire.Doc.FileFormat.PDF);
                        filesStreams.Add(ms1);

                        break;
                    case ".pdf":
                        filesStreams.Add(File.OpenRead(item.ToString()));
                        break;
                    case ".pptx":
                        Presentation ppt = new Presentation(item.ToString(), Spire.Presentation.FileFormat.Auto);
                        ppt.SaveToFile(ms2, Spire.Presentation.FileFormat.PDF);
                        filesStreams.Add(ms2);

                        break;
                    case ".xlsx":
                        Workbook xls = new Workbook();
                        xls.LoadFromFile(item.ToString());
                        xls.SaveToStream(ms3, Spire.Xls.FileFormat.PDF);
                        filesStreams.Add(ms3);

                        break;
                    default:
                        break;

                }
            }
            string outputFile = "result.doc";
            PdfDocumentBase result = PdfDocument.MergeFiles(filesStreams.ToArray());
            //result.SaveToDoc(outputFile);
            result.Save(outputFile,Spire.Pdf.FileFormat.PDF);
            ms1.Close();
            ms2.Close();
            ms3.Close();

    }

Thank you

The error message means your project needs to have a reference to "System.Web". — Lex Li
To me there's a bigger point here. The Spire library is asking you to add web libraries, which likely means that their tools are sending the PDF to their servers for processing. I don't have proof of this but that would make sense. And then you need to ask yourself, am I okay with a third party having access to my documents? — Jordan

Dheeraj Malik Dheeraj Malik · Accepted Answer · 2017-01-03T07:22:28

Add reference of System.Web library by right clicking the project in Solution Explorer window and then clicking Add Reference option from the context menu.

The above action will open up the Add Reference Dialog and from the .Net Tab, you need to choose System.Web library and click OK.

CS0012 C# The type 'HttpContext' is defined in an assembly that is not referenced

1 Answers