c# - 将 session ID 存储为字符串并将其转换回 GUID

Question

我正在尝试使用 session 来存储值 (id)。问题是我必须将它存储为一个字符串。尝试使用 id 的实例时出现错误:

Exception Details: System.InvalidCastException: Specified cast is not valid.

Source Error:

Line 156:        
Line 157:        Nemanet_Navigation newFile = new Nemanet_Navigation();
Line 158:        newFile.Nav_pID = (Guid)Session["id"];
Line 159:       
Line 160:    

这是我获取 ID 的地方，它似乎工作正常。 Session["id"] 获取值。

public void treeview_Navigation_SelectedNodeChanged(object sender, EventArgs e)
    {

        TreeNode node = treeview_Navigation.FindNode(treeview_Navigation.SelectedNode.ValuePath);
        NavTreeNode nNode = node as NavTreeNode;
        Session["id"]=((TreeView)sender).SelectedValue.ToString();
     }

但是这段代码好像不行。我收到上述错误。

protected void Button1_Click(object sender, EventArgs e)
    {


        Nemanet_Navigation newFile = new Nemanet_Navigation();
        newFile.Nav_pID = (Guid)Session["id"];
       }

Answer 1

使用Guid.Parse

protected void Button1_Click(object sender, EventArgs e)
{
    Nemanet_Navigation newFile = new Nemanet_Navigation();
    newFile.Nav_pID = Guid.Parse(Session["id"] as string);
}