HTML Form Editor – C#

HTML Form Element

The HTML Form Element represents a section containing input controls for submitting user information. Using our library, you can easily fulfill the HTML forms and send data directly from your C# application. To make this process much more comfortable, we designed the Aspose.Html.Forms namespace. The main element of this namespace is FormEditor. It allows you to find an existing form in the document, create a new one from scratch, iterate through the elements, fill them up with data, and surely send the information to the remote server.

In this article, you will learn how to work with a FormEditor object to manipulate HTML form in the document, input controls, and submit information. For the testing purpose, we use the form designed by https://httpbin.org service.

How to Use FormEditor

Let’s look at the C# code snippet that demonstrates how to use the Aspose.Html.Forms namespace to programmatically fill and submit an HTML form. You need to follow the next steps:

1. Create a new instance of the HTMLDocument class using HTMLDocument(url) constructor. Specify the URL of the HTML form to be filled out and submitted.
2. Use the Create(document, index) method to create an instance of the FormEditor class, passing in it the HTMLDocument instance and the index of the form being edited (value 0 refers to the first form in the HTML document).
3. Fill the data up using direct access to the input elements and save the filled HTML form to a file. Form fields are accessed and modified using the editor object.
4. Use the FormSubmitter(editor) constructor to create an instance of the FormSubmitter class.
5. Call the Submit() method of the FormSubmitter class to submit the form.
6. Check the status of the form submission result using the IsSuccess property. If the form submission is successful, the response from the server is inspected:
   • if the response is in JSON format, the JSON content is printed to the console;
   • otherwise, the response is loaded into another HTMLDocument instance using the LoadDocument() method for further inspection.

// How to to programmatically fill and submit an HTML form in C#

// Initialize an instance of HTML document
using (HTMLDocument document = new HTMLDocument(Path.Combine(DataDir, "form.html")))
{
    // Create an instance of Form Editor
    using (FormEditor editor = Aspose.Html.Forms.FormEditor.Create(document, 0))
    {
        // You can fill the data up using direct access to the input elements, like this:
        editor["custname"].Value = "John Doe";

        document.Save("out.html");

        // or this:
        TextAreaElement comments = editor.GetElement<Aspose.Html.Forms.TextAreaElement>("comments");
        comments.Value = "MORE CHEESE PLEASE!";

        // or even by performing a bulk operation, like this one:
        editor.Fill(new Dictionary<string, string>()
        {
            {"custemail", "[e-mail]"},
            {"custtel", "[phone]"}
        });

        // Create an instance of form submitter
        using (FormSubmitter submitter = new Aspose.Html.Forms.FormSubmitter(editor))
        {
            // Submit the form data to the remote server
            // If you need you can specify user-credentials and timeout for the request, etc.
            SubmissionResult result = submitter.Submit();

            // Check the status of the result object
            if (result.IsSuccess)
            {
                // Check whether the result is in json format
                if (result.ResponseMessage.Headers.ContentType.MediaType == "application/json")
                {
                    // Dump result data to the console
                    Console.WriteLine(result.Content.ReadAsString());
                }
                else
                {
                    // Load the result data as an HTML document
                    using (Document resultDocument = result.LoadDocument())
                    {
                        // Inspect HTML document here.
                    }
                }
            }
        }
    }
}

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