Trouble Generating Radio Button in Aspose.Pdf

I tried to create radio button using the code from https://docs.aspose.com/pdf/net/add-form-fields/ , but I am getting this error:


An unhandled exception of type ‘System.NullReferenceException’ occurred in Aspose.Pdf.dll
Additional information: Object reference not set to an instance of an object.

This happens when I am try to set the value of the radio button
radio.Value = “”;

and when I try to add radio options
radio.AddOption(“Test”, new Aspose.Pdf.Rectangle(0, 0, 20, 20));

I am using .Net 4.0 with Aspose.Pdf 9.7.0 (latest version on nuget)
I have also included my console application project (Written in Visual Studio 2013).

Could this issue be addressed ASAP or could I get some suggestion for workarounds? I am trying to move away from the older generator and facades namespaces to the newer Apose.Pdf, but I am not able to progress due to this issue.

Hi Sung,

Thanks for your inquiry. Please use the following code snippet to add a radio button in a PDF document. Hopefully, it will help you accomplish the task. We are updating the documentation as well.

string outFile = myDir + "Form_out.pdf";
Document doc = new Document();
Page page = doc.Pages.Add();

//Instantiate a table object
Aspose.Pdf.Table tab1 = new Aspose.Pdf.Table();

//Add the table in paragraphs collection of the desired section
page.Paragraphs.Add(tab1);

//Set with column widths of the table
tab1.ColumnWidths = "100 100";

//Create rows in the table and then cells in the rows

RadioButtonField rf = new RadioButtonField(page);
rf.PartialName = "radio";

doc.Form.Add(rf, 1);

RadioButtonOptionField opt1 = new RadioButtonOptionField();
RadioButtonOptionField opt2 = new RadioButtonOptionField();
opt1.OptionName = "Item1";
opt2.OptionName = "Item2";
opt1.Width = 12;
opt1.Height = 12;
opt2.Width = 12;
opt2.Height = 12;
rf.Add(opt1);
rf.Add(opt2);

opt1.Caption = new TextFragment("Item10");
opt1.Border = new Border(opt1);
opt1.Border.Width = 1;
opt1.Border.Style = Aspose.Pdf.InteractiveFeatures.Annotations.BorderStyle.Solid;
opt1.Characteristics.Border = System.Drawing.Color.Yellow;
opt1.DefaultAppearance.TextColor = System.Drawing.Color.Red;

opt2.Caption = new TextFragment("Item11");
opt2.Border = new Border(opt1);
opt2.Border.Width = 1;
opt2.Border.Style = Aspose.Pdf.InteractiveFeatures.Annotations.BorderStyle.Solid;
opt2.Characteristics.Border = System.Drawing.Color.Yellow;
opt2.DefaultAppearance.TextColor = System.Drawing.Color.Red;

Aspose.Pdf.Row row = tab1.Rows.Add();
Aspose.Pdf.Cell c1 = row.Cells.Add();
c1.Paragraphs.Add(opt1);
Aspose.Pdf.Cell c2 = row.Cells.Add();
c2.Paragraphs.Add(opt2);

doc.Save(outFile);

Please feel free to contact us for any further assistance.

Best Regards,