private string AcquireWebAppAuthorizationCode() { string Code = ""; _resource = GetResourceNameForWebApp(); GetCodeForm getCodeForm = new GetCodeForm(textBox_WebAppClientID.Text, textBox_WebAppRedirectUri.Text, GetResourceURL(_resource)); if (getCodeForm.ShowDialog(out Code) == DialogResult.OK) { if (Code == "") { MessageBox.Show("Getting Authorization Code was failed.", "Office365APIEditor", MessageBoxButtons.OK, MessageBoxIcon.Error); } } else { MessageBox.Show("authentication_canceled: User canceled authentication", "Office365APIEditor", MessageBoxButtons.OK, MessageBoxIcon.Error); } return(Code); }