WebBrowser注入Javascript将焦点设置为第一个输入框

WebBrowser Inject Javascript To Set the Focus to the First Input Box

本文关键字：第一个 输入 设置 焦点 注入 Javascript WebBrowser      更新时间：2023-09-26

我想注入一个javascript，以便将焦点设置为第一个输入框。

我当前的代码是：

Me.WebBrowser1.Focus()
Dim i&
Dim JS(100) As String
'The following Javascript-injection ensures, that the first
'found input-element (if there is one) will be focused
' i = i + 1 : JS(i) = "<script>"
i = i + 1 : JS(i) = "var inputElements = document.getElementsByTagName('input');"
i = i + 1 : JS(i) = "for(i=0; i<inputElements.length; i++)"
i = i + 1 : JS(i) = "{"
i = i + 1 : JS(i) = "  if (inputElements[i].type != 'hidden')"
i = i + 1 : JS(i) = "  {"
i = i + 1 : JS(i) = "    if (inputElements[i].disabled == false)"
i = i + 1 : JS(i) = "    {"
'  If uSetFocusToFirstBox Then
i = i + 1 : JS(i) = "      inputElements[i].focus();"
' End If
'If uScrollIntoView Then
i = i + 1 : JS(i) = "      inputElements[i].scrollIntoView(true);"
'End If
i = i + 1 : JS(i) = "      break;"
i = i + 1 : JS(i) = "    }"
i = i + 1 : JS(i) = "  }"
i = i + 1 : JS(i) = "}"
Dim head As HtmlElement = Me.WebBrowser1.Document.GetElementsByTagName("head")(0)
Dim scriptEl As HtmlElement = Me.WebBrowser1.Document.CreateElement("script")
Dim element As IHTMLScriptElement = DirectCast(scriptEl.DomElement, IHTMLScriptElement)
element.text = Join(JS, "")
head.AppendChild(scriptEl)
Me.WebBrowser1.Document.InvokeScript("sayHello")

有人看到我的错误了吗？

谢谢！

将焦点设置为第一个文本输入

选项1-无脚本

您不需要将脚本注入到文档中。您可以处理DocumentCompleted事件，在那里，使用GetElementByTagName查找输入元素，并使用启用的type="text"查找第一个输入，然后调用Focus()，它还自动将焦点输入滚动到视图：

Private Sub WebBrowser1_DocumentCompleted(sender As Object, e As WebBrowserDocumentCompletedEventArgs) _
    Handles WebBrowser1.DocumentCompleted
    Dim firstTextBox = Me.WebBrowser1.Document.GetElementsByTagName("input") _
                         .Cast(Of HtmlElement)() _
                         .Where(Function(element)
                                    Return element.GetAttribute("type") = "text" And _
                                           element.Enabled = True
                                End Function) _
                         .FirstOrDefault()
    If (firstTextBox IsNot Nothing) Then
        firstTextBox.Focus()
    End If 
End Sub

选项2-注入脚本

出于这个原因，您不需要使用脚本，但为了防止需要注入脚本，这里有一个示例。您应该在项目中添加对Microsoft.mshtml的引用，并编写这样的代码：

Private Sub WebBrowser1_DocumentCompleted(sender As Object, e As WebBrowserDocumentCompletedEventArgs) _
    Handles WebBrowser1.DocumentCompleted
    Dim scriptText = "var inputElements = document.getElementsByTagName('input');" & _
                     "for(i=0; i<inputElements.length; i++){" & _
                     "  if (inputElements[i].type == 'text' && !inputElements[i].disabled){" & _
                     "      inputElements[i].focus();" & _
                     "      inputElements[i].scrollIntoView(true);" & _
                     "      break;" & _
                     "  }" & _
                     "}"
    Dim head As HtmlElement = Me.WebBrowser1.Document.GetElementsByTagName("head")(0)
    Dim script As HtmlElement = Me.WebBrowser1.Document.CreateElement("script")
    Dim scriptElement As IHTMLScriptElement = DirectCast(script.DomElement, IHTMLScriptElement)
    scriptElement.text = scriptText
    head.AppendChild(script)
End Sub
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