注册时出现错误btn

Question

当我填写注册表单并点击按钮移动到用户面板时，它不会移动到用户面板，它会冻结注册。在其背后的用户面板代码显示这样的信息：

Object reference not set to an instance of an object.

protected void btnSave_Click(object sender, EventArgs e) 
    { 
     SqlConnection cn = new SqlConnection(sc); 
     SqlCommand cmd = new SqlCommand(); 

     string sqlstatment = "INSERT INTO UserInfo (UID, FN, LN, Password, RePass, Email,Country, State,City, Post, Img, Logo,RegDate) VALUES (@UID,@FN,@LN,@Password,@RePass,@Email,@Country,@State,@City,@Post,@Img,@Logo,@RegDate)"; 

     cmd.Connection = cn; 
     cmd.CommandType = CommandType.Text; 
     cmd.CommandText = sqlstatment; 

     //Insert the parameters first 
     cmd.Parameters.AddWithValue("@UID", UsrNme.Text); 
     cmd.Parameters.AddWithValue("@FN", fnbox.Text); 
     cmd.Parameters.AddWithValue("@LN", lnamebox.Text); 
     cmd.Parameters.AddWithValue("@Password", passtxtbx1.Text); 
     cmd.Parameters.AddWithValue("@RePass", passtxtbx2.Text); 
     cmd.Parameters.AddWithValue("@Email", emailbox.Text); 
     cmd.Parameters.AddWithValue("@Country", countrdrdolst.SelectedItem.Text); 
     cmd.Parameters.AddWithValue("@State", statedrdolst.SelectedItem.Text); 
     cmd.Parameters.AddWithValue("@City", citiesdrdolst.SelectedItem.Text); 
     cmd.Parameters.AddWithValue("@Post", postbox.Text); 
     cmd.Parameters.AddWithValue("@Img", persimgFileUpload1.FileName); 
     cmd.Parameters.AddWithValue("@Logo", logoFileUpload.FileName); 

     //Get the Current Date Time here 
     cmd.Parameters.AddWithValue("@RegDate", DateTime.Now); 

     if (!string.IsNullOrEmpty(UsrNme.Text)) 
     { 
      Lblcheckusername.Text = "User Name Already Exist"; 
      Lblcheckusername.ForeColor = System.Drawing.Color.Red; 
     } 
     else 
     { 
      Lblcheckusername.Text = "User Name Available"; 
      Lblcheckusername.ForeColor = System.Drawing.Color.Green; 
     } 

     if (persimgFileUpload1.HasFile) 
     { 
      persimgFileUpload1.SaveAs(Server.MapPath("~/images/users/" + persimgFileUpload1.FileName)); 
     } 

     if (logoFileUpload.HasFile) 
     { 
      logoFileUpload.SaveAs(Server.MapPath("~/images/Logos/" + logoFileUpload.FileName)); 
     } 

     SqlDataAdapter ad = new SqlDataAdapter(cmd); 
     DataSet ds = new DataSet(); 
     ad.SelectCommand = cmd; 
     ad.Fill(ds); 
     Response.Redirect("User panel.aspx"); 
    } 

这里是在第一代码行出现错误的用户面板代码隐藏：

USRNMElbl.Text = Session["UsrNme"].ToString(); 
if (Session["UsrNme"] != null) 
{ 
} 

if (!Page.IsPostBack) 
{ 
    DataTable countrycascd = new DataTable(); 
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["BeravaConnectionString"].ConnectionString)) 
    { 
     SqlDataAdapter adaptar = new SqlDataAdapter("select [countryID],[country] FROM [countr]", con); 
     adaptar.Fill(countrycascd); 
     countrdrdolst.DataSource = countrycascd; 
     countrdrdolst.DataTextField = "country"; 
     countrdrdolst.DataValueField = "countryID"; 
     countrdrdolst.DataBind(); 
    } 
    countrdrdolst.Items.Insert(0, new ListItem("Välj land", "0")); 
} 

if (!Page.IsPostBack) 
{ 
    DataTable Sectiondt = new DataTable(); 
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["BeravaConnectionString"].ConnectionString)) 
    { 
     SqlDataAdapter adaptar = new SqlDataAdapter("select [CateID],[Category] FROM [Section]", con); 
     adaptar.Fill(Sectiondt); 
     Catedrdoads.DataSource = Sectiondt; 
     Catedrdoads.DataTextField = "Category"; 
     Catedrdoads.DataValueField = "CateID"; 
     Catedrdoads.DataBind(); 
    } 
    Catedrdoads.Items.Insert(0, new ListItem("Select Section", "0")); 
} 
} 

protected void LinkButton1_Click(object sender, EventArgs e) 
{ 
    MultiView1.ActiveViewIndex = 0; 
} 
protected void LinkButton2_Click(object sender, EventArgs e) 
{ 
    MultiView1.ActiveViewIndex = 1; 
} 
protected void LinkButton3_Click(object sender, EventArgs e) 
{ 
    MultiView1.ActiveViewIndex = 2; 
} 
protected void LinkButton4_Click(object sender, EventArgs e) 
{ 
    MultiView1.ActiveViewIndex = 3; 
} 
protected void addadsbtn_Click(object sender, EventArgs e) 
{ 
    Guid newGUID = Guid.NewGuid(); 
    SqlConnection cn = new SqlConnection(sc); 
    SqlCommand cmd = new SqlCommand(); 
    string sqlstatment = "INSERT INTO [ads] ([Section], [Category], [UID], [AdsTit], [AdsDesc], [Country], [State], [City], [AdsPrice], [Img1], [img2], [img3], [img4], [img5], [Wtags]) VALUES (@Section, @Category, @UID, @AdsTit, @AdsDesc, @Country, @State, @City, @AdsPrice, @Img1, @img2, @img3, @img4, @img5, @Wtags)"; 

    cmd.Connection = cn; 
    cmd.CommandType = CommandType.Text; 
    cmd.CommandText = sqlstatment; 

    //Insert the parameters first 
    cmd.Parameters.AddWithValue("@Section", Catedrdoads.SelectedItem.Text); 
    cmd.Parameters.AddWithValue("@Category", SubCatedrdoads.SelectedItem.Text); 
    cmd.Parameters.AddWithValue("@UID", USRNMElbl.Text); 
    cmd.Parameters.AddWithValue("@AdsTit", addadstittxtbx.Text); 
    //cmd.Parameters.AddWithValue("@AdsDesc", Editor1.Text); 
    cmd.Parameters.AddWithValue("@Country", countrdrdolst.SelectedItem.Text); 
    cmd.Parameters.AddWithValue("@State", statedrdolst.SelectedItem.Text); 
    cmd.Parameters.AddWithValue("@City", citiesdrdolst.SelectedItem.Text); 
    cmd.Parameters.AddWithValue("@AdsPrice", adsaddpristxtbx.Text); 
    cmd.Parameters.AddWithValue("@Img1", FileUpload1.FileName); 
    cmd.Parameters.AddWithValue("@Img2", FileUploadImg2.FileName); 
    cmd.Parameters.AddWithValue("@Img3", FileUploadImg3.FileName); 
    cmd.Parameters.AddWithValue("@Img4", FileUploadImg4.FileName); 
    cmd.Parameters.AddWithValue("@Img5", FileUploadImg5.FileName); 
    cmd.Parameters.AddWithValue("@Wtags", addadswtagtxtbtn.Text); 

    SqlDataAdapter ad = new SqlDataAdapter(cmd); 
    DataSet ds = new DataSet(); 
    ad.SelectCommand = cmd; 
    ad.Fill(ds); 

    Response.Redirect("User panel.aspx"); 
} 

Answer 1

问题可能您的会话[“UsrNme”]为空

if (Session["UsrNme"] != null) 
{ 
     USRNMElbl.Text = Session["UsrNme"].ToString(); 
} 
else 
{ 
    return; 
} 

您还可以阅读http://www.codingdefined.com/2014/06/object-reference-not-set.html