如何创建一个包含 2 个以上参数的扩展方法？

Question

I have two classes in my Azure Functions project.

MyExtensions.cs:

namespace My.Functions
{
public static class MyExtensions
{
    public static async Task<(bool addedcontactmail, string errorline1, string errorline2, string errorline3, string errorline4)> AddEmail(this string emailaddress, PlayFabClientInstanceAPI clientAPI, string language)
    {
        bool addedcontactmail = false;
        string errorline1 = string.Empty;
        string errorline2 = string.Empty;
        string errorline3 = string.Empty;
        string errorline4 = string.Empty;

        var request = new PlayFab.ClientModels.AddOrUpdateContactEmailRequest();
        request.EmailAddress = emailaddress;
        var result = await clientAPI.AddOrUpdateContactEmailAsync(request);

        if (result.Error != null)
        {
            errorline1 = "Error.";
            errorline2 = "Please try again.";
        }
        else
        {
            addedcontactmail = true;
        }
          return (addedcontactmail, errorline1, errorline2, errorline3, errorline4);
    }
}
}

I have tried to call the extension method AddEmail in my class NewFunstions.cs but it only seems to work if AddEmail takes only two parameters:

If MyExtensions.AddEmail only takes two parameters, then it shows a menu with the return variables:

If MyExtensions.AddEmail takes three parameters:

In NewFunctions.cs, I call the extension method:

    var resultcontactemail = await MyExtensions.AddEmail(desiredemail, clientAPI, language);
    if (resultcontactemail.)
    {
        functionsuccessful = resultcontactemail.addedcontactmail;
        errorline1 = resultcontactemail.errorline1;
        errorline2 = resultcontactemail.errorline2;
        errorline3 = resultcontactemail.errorline3;
        errorline4 = resultcontactemail.errorline4;
    }

As you can see in the picture, it's not possible to choose the return variables addedcontactmail, errorline1, errorline2, errorline3, errorline4 from the menu if the extension method takes three parameters. Why is it not showing the return variables in a menu?

Why is my extension method not working if it takes more than two parameters? Is it possible to create an extension method in Azure Functions that takes more than two parameters?

Answer 1

Remove this inside the first parameter of AddEmail method. It will no longer be a proper extension method, but it will solve your problem.

Continue reading if you want to know what is wrong with your extension method:

this string means you are extending a string, so you must call it from an instance of string . The mistake you are making is that you are calling it from the class MyExtensions.AddEmail . I don't think it makes sense to extend a string for this so I believe my solution will put you back on the right track. See more about it in the docs . Specifically step 5.

5. Call the methods as if they were instance methods on the type