登录asp.net后如何检索当前用户的用户名

Question

I need to get the user current name after a log in. I need to display the name in the page, like welcome user . Please help me, my current code is given below

protected void Button1_Click(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con1"].ConnectionString);
        con.Open();
        SqlCommand cmdr = new SqlCommand("Select name,password From registration", con);
        SqlDataReader dr = cmdr.ExecuteReader();
        while (dr.Read())
        {
            if (txt_name.Text == dr[0].ToString() && txt_pass.Text == dr[1].ToString())
            {
                Response.Redirect("logout.aspx");
            }
            else
            {
                label4.Text ="Invalid Username/Password";
            }
        }

    }

Answer 1

If you're using the ASP.NET membership :

string userName = Membership.GetUser().UserName

However, obviously you are not using it (i strongly recommend). Why do you redirect to logout.aspx when the user successfully provided his username and password?

Apart from that you're not using the provided informatiuons at all in your query.

SqlCommand cmdr = new SqlCommand("Select name,password From registration", con);

So you should use parameters to filter for the correct record:

using(var cmdr = new SqlCommand("Select name,password From registration where name=@name and password=@password", con))
{
    cmdr.Parameters.AddWithValue("@name", userName);
    cmdr.Parameters.AddWithValue("@password", password);
    if(cmdr.ExecuteReader().HasRows)
    {
        // user + password correct
    }
    else
    {
        // user or password incorrect
    }
}

Answer 2

Membership.GetUser().UserName in a membership provider. Under no circumstances should you run the code you have there. It is asking for a hack. You should not be loading the passwords into memory and you are going to have performance issues as you gain more users because of your loop through all users!

Answer 3

protected void Button1_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con1"].ConnectionString);
    con.Open();
    SqlCommand cmdr = new SqlCommand("Select name,password From registration", con);
    SqlDataReader dr = cmdr.ExecuteReader();
    while (dr.Read())
    {
        if (txt_name.Text == dr[0].ToString() && txt_pass.Text == dr[1].ToString())
        {
            Session["UserName"]=dr[0].ToString(); // OR Session["UserName"]=txt_name.Text;
            Response.Redirect("logout.aspx");
        }
        else
        {
            label4.Text ="Invalid Username/Password";
        }
    }

}

You can fetch the session values in HTML(if your using it in your application)

<div>
Welcome <%=HttpContext.Current.Session["UserName"]%>
</div>

Answer 4

You should be able to get the identity of the user from the User property in code-behind.

myLabel.Text = User.Identity.Name;

The full namespace etc. for this is HttpContext.Current.User.Identity.Name .

Reference for HttpContext.User property: http://msdn.microsoft.com/en-us/library/system.web.httpcontext.user.aspx

Answer 5

put the username in a session

Session["username"] = dr[0].ToString();

then on the other page

if Session["username"] != null
{
  String username = Session["username"].ToString();
}
else
{
  Page.Redirect("login.aspx");
}

You can check each different page

Answer 6

You should ideally use built-in ASP.NET Forms Authentication - see this article for quick start. Coming to your question, on successful login, you should use line such as

FormsAuthentication.RedirectFromLoginPage(txt_name.Text, true);

This would store the user name into authentication cookie and which can be subsequently retrieved using code such as User.Identity.Name that you can user anywhere in your pages.

Answer 7

You can store the username in session object and get username anywhere in the application if session is present

But you have to update your query also, The way you are calling is not good approach

protected void Button1_Click(object sender, EventArgs e)
    {
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["con1"].ConnectionString);
        con.Open();
        SqlCommand cmdr = new SqlCommand("Select name From registration where name = @username and password = @password", con);
        cmdr.Parameters.Add("@username", txt_name.Text.trim());
        cmdr.Parameters.Add("@password", txt_pass.Text.trim());

        SqlDataReader dr = cmdr.ExecuteReader();

        if(cmdr.ExecuteReader().HasRows)
        {
             Response.Redirect("logout.aspx");
             Session["userName"] = txt_name.Text.trim();
        }
        else{
        //Error page path
        }               
        //DOn't forget to close the connection when you Open it
      con.Close();
    }

You should learn more from some tutorials:

1. http://csharp-station.com/Tutorial/AdoDotNet/Lesson01
2. MSDN

Answer 8

..并且如果您只想使用User对象：

var username = User.Identity.Name;