C# .NET PDF form library

The guide explains how to fill form fields programmatically in a PDF document. This feature enables you to, for example, fill in many forms in one go with values from a database.

To fill form fields programmatically in a PDF document, follow the steps below:

  1. Create a GdPicturePDF object.
  2. Determine the number of form fields in the document with the GetFormFieldsCount method.
  3. Loop through the form fields.
  4. For each form field, determine the title with the GetFormFieldId and GetFormFieldTitle methods.
  5. If the title matches your conditions, such as family or given name, set a value for the form field with the SetFormFieldValue method.
  6. Save the output in a new PDF file with the SaveToFile method.

The code below opens a fillable PDF document, fills in two form fields, and saves the output in a new PDF file:

using GdPicturePDF gdpicturePDF = new GdPicturePDF();
// Load the source document.
gdpicturePDF.LoadFromFile(@"C:\temp\source.pdf");
// Determine the number of form fields.
int formFieldCount = gdpicturePDF.GetFormFieldsCount();
// Loop through the form fields.
for (int formFieldIndex = 0; formFieldIndex <= formFieldCount - 1; formFieldIndex++)
{
    // Determine the title of the form field.
    int formFieldId = gdpicturePDF.GetFormFieldId(formFieldIndex);
    string formFieldTitle = gdpicturePDF.GetFormFieldTitle(formFieldId);
    // Set a value for the form field.
    if (formFieldTitle== "Family Name")
    {
        gdpicturePDF.SetFormFieldValue(formFieldId, "Doe");
    }
    else if (formFieldTitle == "Given Name")
    {
        gdpicturePDF.SetFormFieldValue(formFieldId, "Jane");
    }
}
// Save the output in a new PDF file.
gdpicturePDF.SaveToFile(@"C:\temp\output.pdf");

Used Methods and Properties

Related Topics