Question

我想创建一个自动填充我的Web表单并执行某些操作的应用程序。我的应用程序有一个显示网页的Web浏览器控件。生成错误的WebBrowser1_DocumentCompleted Eventhandler方法的代码

private void webBrowser1_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
    HtmlDocument obj = (HtmlDocument)webBrowser1.Document;
    HtmlElement txtFirst = obj.GetElementById("txtFirstNo");
    HtmlElement txtSecond = obj.GetElementById("txtSecond");
    HtmlElement chk = obj.GetElementById("Checkbox1");
    txtFirst.SetAttribute("value", "111");
    txtSecond.SetAttribute("value", "123456");
    chk.InvokeMember("CLICK");
    HtmlElement btn = obj.GetElementById("Submit1");
    btn.InvokeMember("CLICK");
}

它符合

的错误

txtFirst.SetAttribute（“value”，“111”）;

对象引用没有设置对象的实例我不明白为什么会给出这个错误。

当我检查

时，在即时窗口中

txtFirst.SetAttribute（“value”，“111”）

它给出了

{System.Windows.Forms.HtmlElement}
    All: {System.Windows.Forms.HtmlElementCollection}
    CanHaveChildren: false
    Children: {System.Windows.Forms.HtmlElementCollection}
    ClientRectangle: {X = 0 Y = 0 Width = 170 Height = 17}
    Document: {System.Windows.Forms.HtmlDocument}
    DomElement: {mshtml.HTMLInputElementClass}
    Enabled: true
    FirstChild: null
    Id: "txtFirstNo"
    InnerHtml: null
    InnerText: null
    Name: "txtFirstNo"
    NextSibling: null
    OffsetParent: {System.Windows.Forms.HtmlElement}
    OffsetRectangle: {X = 3 Y = 4 Width = 170 Height = 17}
    OuterHtml: "<INPUT id=txtFirstNo style=\"BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none; BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; WIDTH: 170px\" value=11104803 name=txtFirstNo>"
    OuterText: null
    Parent: {System.Windows.Forms.HtmlElement}
    ScrollLeft: 0
    ScrollRectangle: {X = 0 Y = 0 Width = 170 Height = 17}
    ScrollTop: 0
    Style: "BORDER-TOP-STYLE: none; BORDER-LEFT-STYLE: none; BORDER-BOTTOM-STYLE: none; BORDER-RIGHT-STYLE: none; WIDTH: 170px"
    TabIndex: 0
    TagName: "INPUT"

对象引用未设置对象实例，同时访问C＃Web浏览器DOM元素

0 个答案: