0

Hi,

I have a gridview that displays all the users from the ASPDOTNET database and I have some buttons that I can display other details and also edit and delete a user.
The show button seems to only work on every other row.

The fail message is the following:

Object reference not set to an instance of an object. 
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error: 


Line 126:        Button b = (Button)sender;
Line 127:        MembershipUser user = Membership.GetUser(b.CommandArgument.ToString());
Line 128:        ViewState["username"] = user.UserName;
Line 129:        Label21.Text = "" + user.UserName;
Line 130:        DropDownList ddl = (DropDownList)GridView1.Rows[int.Parse(b.CommandName)].FindControl("DropDownList1");

Here is the code

<asp:Panel 
            runat="server" 
            ID="panel8" 
            GroupingText="Manage Users"> 
        <asp:GridView
            ID="GridView1" 
            runat="server" 
            AllowPaging="True" 
            AutoGenerateColumns="False" 
            OnPageIndexChanging="GridView1_PageIndexChanging"
            OnRowDataBound="GridView1_RowDataBound" 
            PageSize="4" 
            OnPageIndexChanged="GridView1_PageIndexChanged" 
            Width="100%" 
            OnRowCancelingEdit="GridView1_RowCancelingEdit" 
            OnRowEditing="GridView1_RowEditing" 
            OnRowUpdating="GridView1_RowUpdating" 
            OnRowDeleting="GridView1_RowDeleting" 
            GridLines="None">
        <RowStyle />
        <Columns>
        <asp:TemplateField HeaderText="">
        <ItemTemplate>
            <table style="width: 100%">
                <tr>
                    <td>
                        <asp:Label 
                            ID="Label16" 
                            runat="server" 
                            Text="UserName" 
                            Font-Bold="true">
                        </asp:Label>
                    </td>
                    <td>
                        <asp:Label 
                            ID="Label39" 
                            runat="server" 
                            Text="Email Address" 
                            Font-Bold="true">
                        </asp:Label>
                    </td>
                </tr>
                <tr>
                    <td align="left">
                        <asp:Label  
                            ID="Label1" 
                            runat="server"  
                            Font-Bold="False" 
                            Text='<%# Eval("UserName") %>'>
                        </asp:Label>
                    </td>
                    <td align="left">
                        <asp:HyperLink 
                            ID="HyperLink1" 
                            runat="server" 
                            Font-Bold="False" 
                            NavigateUrl='<%# "mailto:" + Eval("Email") %>'
                            Text='<%# Eval("Email") %>'>
                        </asp:HyperLink>
                    </td>
                </tr>
                <tr>
                    <td align="left" nowrap="nowrap">
                        <asp:Label 
                            ID="Label36" 
                            runat="server" 
                            Text='<%# Eval("Comment") %>'>
                        </asp:Label>
                    </td>
                </tr>
                <tr>
                    <td align="left" nowrap="noWrap" colspan="2">
                        <br />
                        <asp:Button 
                            ID="Button15"
                            runat="server" 
                            CommandName="Edit" 
                            Text="Edit" />
                        <asp:Button 
                            ID="Button12" 
                            runat="server" 
                            Text="Delete" 
                            CommandName="Delete" />
                        <asp:DropDownList ID="DropDownList1" runat="server">
                            <asp:ListItem>Profile</asp:ListItem>
                            <asp:ListItem>Roles</asp:ListItem>                                
                            <asp:ListItem>Activity</asp:ListItem>
                            <asp:ListItem>Status</asp:ListItem>
                            <asp:ListItem>Security</asp:ListItem>
                        </asp:DropDownList>
                        <asp:Button 
                            ID="Button1" 
                            runat="server" 
                            CommandName="show" 
                            Text="Show" 
                            OnClick="Button1_Click1" />
                        <br />
                        <hr />
                    </td>
                </tr>
            </table>
        </ItemTemplate>
        <EditItemTemplate>
            <table style="width: 100%">
                <tr>
                    <td colspan="2" nowrap="nowrap">
                        <asp:Label 
                            ID="Label1" 
                            runat="server" 
                            Font-Bold="True" 
                            Text='<%# Eval("UserName") %>'>
                        </asp:Label>
                    </td>
                </tr>
                <tr>
                    <td nowrap="nowrap">
                        <asp:Label ID="Label37" 
                            runat="server" 
                            Text="Email :">
                        </asp:Label>
                    </td>
                    <td nowrap="noWrap">
                        <asp:TextBox 
                            ID="TextBox12" 
                            runat="server" 
                            Text='<%# Eval("Email") %>'>
                        </asp:TextBox>
                    </td>
                </tr>
                <tr>
                    <td align="left" nowrap="nowrap">
                        <asp:Label 
                            ID="Label38" 
                            runat="server" 
                            Text="Comments :">
                        </asp:Label></td>
                    <td align="left" nowrap="nowrap">
                        <asp:TextBox 
                            ID="TextBox13" 
                            runat="server" 
                            TextMode="MultiLine" 
                            Text='<%# Eval("Comment") %>'>
                        </asp:TextBox></td>
                </tr>
                <tr>
                    <td align="left" colspan="2" nowrap="nowrap">
                        <asp:Button 
                            ID="Button13" 
                            runat="server" 
                            CommandName="Update" 
                            Text="Save" />
                        <asp:Button 
                            ID="Button14" 
                            runat="server" 
                            CommandName="Cancel" 
                            Text="Cancel" />
                    </td>
                </tr>
                </table>
            </EditItemTemplate>
            </asp:TemplateField>
        </Columns>
        </asp:GridView>
        </asp:Panel>

and the C# (from the fail code for line 128 is line 7 shown below)

#region Show Button Event

    protected void Button1_Click1(object sender, EventArgs e)
    {
        Button b = (Button)sender;
        MembershipUser user = Membership.GetUser(b.CommandArgument.ToString());
        ViewState["username"] = user.UserName;
        Label21.Text = "" + user.UserName;
        DropDownList ddl = (DropDownList)GridView1.Rows[int.Parse(b.CommandName)].FindControl("DropDownList1");
        switch (ddl.SelectedValue)
        {
            case "Status":
                CheckBox1.Checked = user.IsApproved;
                CheckBox2.Checked = user.IsLockedOut;
                CheckBox3.Checked = user.IsOnline;
                if (user.IsLockedOut)
                {
                    CheckBox2.Enabled = true;
                }
                else
                {
                    CheckBox2.Enabled = false;
                }
                MultiView1.ActiveViewIndex = 0;
                break;
            case "Activity":
                Label11.Text = user.CreationDate.ToString();
                Label12.Text = user.LastActivityDate.ToString();
                Label13.Text = user.LastLockoutDate.ToString();
                Label14.Text = user.LastLoginDate.ToString();
                Label15.Text = user.LastPasswordChangedDate.ToString();
                MultiView1.ActiveViewIndex = 1;
                break;
            case "Security":
                Label22.Text = user.PasswordQuestion;
                if (!Membership.Provider.EnablePasswordReset)
                {
                    Button5.Enabled = false;
                }
                if (!Membership.Provider.EnablePasswordRetrieval)
                {
                    Button4.Enabled = false;
                }
                if (Membership.Provider.PasswordFormat == MembershipPasswordFormat.Hashed)
                {
                    Button4.Enabled = false;
                    Button5.Enabled = false;
                }
                MultiView1.ActiveViewIndex = 2;
                break;
            case "Roles":
                string[] roles = Roles.GetAllRoles();
                FillControlsWithRoles(roles);
                string[] userroles = Roles.GetRolesForUser(user.UserName);
                foreach (string s in userroles)
                {
                    ListItem li = CheckBoxList1.Items.FindByValue(s);
                    if (li != null)
                        li.Selected = true;
                }
                MultiView1.ActiveViewIndex = 3;
                break;
            case "Profile":
                ProfileCommon pc = Profile.GetProfile(user.UserName);
                DropDownList3.Items.Clear();
                foreach (SettingsProperty p in ProfileCommon.Properties)
                {
                    DropDownList3.Items.Add(p.Name);
                }
                MultiView1.ActiveViewIndex = 4;
                break;

        }

    }

    #endregion

Thanks for looking.

Cheers Rob.

1
Contributor
2
Replies
3
Views
6 Years
Discussion Span
Last Post by RobM_01
0

Hi,

each row in the grid has a show button to display other user details, but it only works on rows 1,3,5,... and so on. It fails on rows 2,4,6... onwards.

I don't have enough knowledge in C# to figure out what is happening here, any help will be greatly appreciated.

Many thanks,

Cheers Rob.

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