Null Exception while passing password to Gmail suing C#

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C#

Gmail

Hi,

I am trying to create a web form where clicking on button will open Gmail in IE.

Below is the code I am using, when I run it and click on Open Gmail button I am getting error at underlined line.

I have tried both Passwd and passwd-hidden but get same error.

Also, I want to know how can I read my password from a secure place and not hardcode it in code.

Thanks for your help in advance.

private void button2_Click(object sender, EventArgs e)
        {


            //second try
            //open Gmail
            InternetExplorer explorer = new InternetExplorer();

            explorer.DocumentComplete += OnIEDocumentComplete;

            // Setting the documentComplete Event to false
            documentComplete = new AutoResetEvent(false);

            object mVal = System.Reflection.Missing.Value;
            explorer.Navigate("http://www.gmail.com", ref mVal, ref mVal, ref mVal, ref mVal);

            // Waiting for the document to load completely
            documentComplete.WaitOne();

            HTMLDocument doc = (HTMLDocument)explorer.Document;

            HTMLInputElement userID = (HTMLInputElement)doc.all.item("Email", 0);
            userID.value = "abc@gmail.com";
            HTMLInputElement pwd = (HTMLInputElement)doc.all.item("Passwd-hidden", 0);
            pwd.value = "abcdef";
            HTMLInputElement btnsubmit = (HTMLInputElement)doc.all.item("signIn", 0);
            btnsubmit.click();
            explorer.Visible = true;
        }

Error:

An unhandled exception of type 'System.NullReferenceException' occurred in WindowsFormsApplication1.exe

Additional information: Object reference not set to an instance of an object.