神马品牌网宫城县仙台市:.net xml.node 未将对象引用设置到对象的实例错误
来源：百度文库 编辑：神马品牌网 时间：2024/05/02 09:04:37
.net xml.node 未将对象引用设置到对象的实例错误
程序如下：
Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
Dim node As System.Xml.XmlNode
node = doc.SelectSingleNode("rss/channel/item/title[@title='" + ListBox1.SelectedItem + "']")
Dim mystr As String
’为什么到这里就报错？“未将对象引用设置到对象的实例”
mystr = node.InnerText
End Sub
程序如下：
Private Sub ListBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
Dim node As System.Xml.XmlNode
node = doc.SelectSingleNode("rss/channel/item/title[@title='" + ListBox1.SelectedItem + "']")
Dim mystr As String
’为什么到这里就报错？“未将对象引用设置到对象的实例”
mystr = node.InnerText
End Sub
因为如果这句doc.SelectSingleNode("rss/channel/item/title[@title='" + ListBox1.SelectedItem + "']")返回的是一个空值，就会出现这个问题，即没有找到这个节点，一个可靠的方法是加上，
if(not node is nothing)then
mystr = node.InnerText
end if