如何检查返回值是否为null vb.net

Question

我开始创建一个自动按下我的网页上的按钮的应用程序 它的工作完美的代码，但我如何检查返回值是否为null？ 这是我的代码

Public Class Form5
Dim CheckButton, skip_button As HtmlElement
Private Sub Form5_Load(sender As Object, e As EventArgs) Handles MyBase.Load

End Sub

Private Sub WebBrowser1_DocumentCompleted(sender As Object, e As WebBrowserDocumentCompletedEventArgs) Handles WebBrowser1.DocumentCompleted
    skip_button = WebBrowser1.Document.GetElementById("skip_button")
    CheckButton = WebBrowser1.Document.GetElementById("skip_button")

    skip_button.InnerText = "skip_button" 'Replace testID by the ID you want


End Sub
End Class

Answer 1

您可以查看GetElementById的结果，如下所示：

 FRM_RECEIPTS frm = new FRM_RECEIPTS();
 FRM_RECEIPTS.getMainForm.dgvRecipts.DataSource = null;
 FRM_RECEIPTS.getMainForm.dgvRecipts.DataSource = receipt.SearchRecepits(frm.txtSearch.Text, frm.coBoxState.Text);