vb.net 檢測網(wǎng)絡(luò)連接

既然從網(wǎng)上找的實(shí)例沒問題，也許就是調(diào)用的時(shí)候沒出來或者在檢測網(wǎng)卡當(dāng)中出現(xiàn)了問題。

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VB.NET如何判斷電腦是否已連接到網(wǎng)絡(luò)？

Microsoft.VisualBasic.Devices.Network.IsAvailable As Boolean

生成實(shí)例后可以通過此屬性來獲取是否聯(lián)網(wǎng)的值，True代表已聯(lián)網(wǎng)，F(xiàn)alse代表沒有聯(lián)網(wǎng)

Microsoft.VisualBasic.Devices.Network.NetworkAvailabilityChanged(ByVal Object, ByVal Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs)

該事件是在電腦斷開/連上互聯(lián)網(wǎng)是引發(fā)的

其中：

e.IsNetworkAvailable

的功能同Microsoft.VisualBasic.Devices.Network.IsAvailable

實(shí)例:

Dim?netListener?As?New?Microsoft.VisualBasic.Devices.Network?'生成實(shí)例

If?netListener.IsAvailable?=?True?Then

MsgBox("已聯(lián)網(wǎng)")

Else

MsgBox("未聯(lián)網(wǎng)")

End?If

NetworkAvailabilityChanged實(shí)例：

WithEvents?netListener?As?New?Microsoft.VisualBasic.Devices.Network?'生成實(shí)例

Private?Sub?OnNetworkChanged(ByVal?Object,?ByVal?Microsoft.VisualBasic.Devices.NetworkAvailableEventArgs)Handles?netListener.NetworkAvailabilityChanged

If?e.IsNetworkAvailable?=?True?Then

MsgBox("已聯(lián)網(wǎng)")

Else

MsgBox("未聯(lián)網(wǎng)")

End?If

End?Sub

vb.net中如何判斷網(wǎng)絡(luò)連接？

新建模塊

Function IsHearOK(ByVal URL As String) As Boolean '判斷網(wǎng)頁是否存在函數(shù)

Dim XMLObject As Object, ReturnType As String

XMLObject = CreateObject("Microsoft.XMLHTTP")

XMLObject.Open("GET", URL, False)

XMLObject.setRequestHeader("CONTENT-TYPE", "application/x-www-form-urlencoded")

XMLObject.setRequestHeader("Range", "bytes=1-255")

Try

XMLObject.Send()

If XMLObject.Status = 200 Or XMLObject.Status = 206 Then

ReturnType = XMLObject.getResponseHeader("CONTENT-TYPE")

If UCase(ReturnType) "TEXT/HTML" Then

IsHearOK = True

Else

IsHearOK = False

End If

Else

IsHearOK = False

End If

Catch

MsgBox("連接異常，請檢查網(wǎng)絡(luò)！", , "提醒")

XMLObject = Nothing

End Try

End Function

調(diào)用 ishearok（url）=true 正常