I know this is old hat, but after recently having a conversation with one of the ASP.NET Team guys about how easy Web Forms is to use, I thought I’d just post a simple example of that.  Here is the scenario.  You have a simple GridView with just three columns (Select,Id,TagName).  You want to be able to capture what happens when the user pressed the Select command and capture the Id.  It looks like this:

And has an aspx page like this:

<asp:GridView ID="GridViewNotSelected" runat="server" AllowSorting="True"         AutoGenerateColumns="False"         DataSourceID="SqlDataSourceTagsNotSelected"         onrowcommand="GridViewNotSelected_RowCommand">    <Columns>        <asp:TemplateField ShowHeader="False">            <ItemTemplate>                <asp:LinkButton ID="LinkButton1" runat="server"                     CausesValidation="False" CommandArgument='<%# Eval("Id") %>'                    CommandName="Select" Text="Select"></asp:LinkButton>            </ItemTemplate>        </asp:TemplateField>        <asp:TemplateField             HeaderText="&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;&amp;nbsp;">        </asp:TemplateField>        <asp:TemplateField>            <ItemTemplate>                <asp:Label ID="Label1" Text='<%# Eval("TagName") %>' runat="server"></asp:Label>            </ItemTemplate>        </asp:TemplateField>    </Columns></asp:GridView>

Notice that in the TemplateField there is LinkButton with a CommandArgument that simply extracts the TagName with the current Id of the SqlDataSource.  Now, all you need is the RowCommand event and you are done.  Here it is in C#.

protected void GridViewNotSelected_RowCommand(object sender, GridViewCommandEventArgs e){    int tagsId = Convert.ToInt32(e.CommandArgument);}

And finally, the proof!

Very very simple.  HTH’s.

So, you have a GridView or DetailsView that has standard “Edit” “Update” “New” type command buttons on them.  The way they get there is by having the declaration something like this:

 <asp:DetailsView ID="DetailsView1" runat="server" Height="50px" Width="125px"
            AllowPaging="True" AutoGenerateRows="False" DataKeyNames="Id"
            DataSourceID="SqlDataSource1">
            <Fields>
                <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True"
                    SortExpression="Id" />
                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                <asp:BoundField DataField="CampStartDate" HeaderText="CampStartDate"
                    SortExpression="CampStartDate" />
                <asp:BoundField DataField="CampEndDate" HeaderText="CampEndDate"
                    SortExpression="CampEndDate" />
                <asp:CommandField ShowEditButton="True" ShowInsertButton="True" />
            </Fields>
</asp:DetailsView>

What you want is to say something like:

“I only want admin’s to be able to add new rows so  want to hide the “new” button based on that”

So, first thing is to convert the field to a template from the following menu.  You do this by using the little helper in the upper right hand corner of the detailsview (in design mode), chose Edit Fields, CommandField, then convert to template (as in the picture below).

Then, you will have something like this:

 <asp:DetailsView ID="DetailsView1" runat="server" Height="50px" Width="125px"
            AllowPaging="True" AutoGenerateRows="False" DataKeyNames="Id"
            DataSourceID="SqlDataSource1">
            <Fields>
                <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True"
                    SortExpression="Id" />
                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
                <asp:BoundField DataField="CampStartDate" HeaderText="CampStartDate"
                    SortExpression="CampStartDate" />
                <asp:BoundField DataField="CampEndDate" HeaderText="CampEndDate"
                    SortExpression="CampEndDate" />
                <asp:TemplateField ShowHeader="False">
                    <ItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False"
                            CommandName="Edit" Text="Edit"></asp:LinkButton>
                        &nbsp;<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False"
                            CommandName="New" Text="New"></asp:LinkButton>
                    </ItemTemplate>
                    <EditItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True"
                            CommandName="Update" Text="Update"></asp:LinkButton>
                        &nbsp;<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False"
                            CommandName="Cancel" Text="Cancel"></asp:LinkButton>
                    </EditItemTemplate>
                    <InsertItemTemplate>
                        <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="True"
                            CommandName="Insert" Text="Insert"></asp:LinkButton>
                        &nbsp;<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False"
                            CommandName="Cancel" Text="Cancel"></asp:LinkButton>
                    </InsertItemTemplate>
                </asp:TemplateField>
            </Fields>
</asp:DetailsView>

Now, you have standard <asp:LinkButton> so you can call the visible property from your codebehind like this:

 <asp:TemplateField ShowHeader="False">
                     <ItemTemplate>
                         <asp:LinkButton ID="LinkButton1" runat="server" CausesValidation="False" Visible='<%# GetShowEditButton() %>'
                             CommandName="Edit" Text="Edit"></asp:LinkButton>
                         &nbsp;<asp:LinkButton ID="LinkButton2" runat="server" CausesValidation="False" Visible='<%# GetShowInsertButton() %>'
                             CommandName="New" Text="New"></asp:LinkButton>
                         &nbsp;<asp:LinkButton ID="LinkButton3" runat="server" CausesValidation="False"
                             CommandName="Delete" Text="Delete" Visible='<%# GetShowDeleteButton() %>'     ></asp:LinkButton>
                     </ItemTemplate>
</asp:TemplateField>

Then, in your codebehind, you have the following:

 protected bool GetShowEditButton()
    {
        return Roles.IsUserInRole("Admin");
    }

    protected bool GetShowInsertButton()
    {
        return Roles.IsUserInRole("Admin");
    }
    protected bool GetShowDeleteButton()
    {
        return Roles.IsUserInRole("Admin");
    }
}

Hope you find this before spending a bunch of time reading about more complicated solutions.

   1: <%@ Master Language="C#" MasterPageFile="~/MasterPages/MasterPage.Master" AutoEventWireup="true"

   2:     CodeBehind="ContactMasterPage.master.cs" Inherits="ThreePLogic.Web.ASPWeb.ContactPages.ContactMasterPage" %>

   3:  

   4: <asp:Content ID="Content5" ContentPlaceHolderID="ContentCenter" runat="server">

   5:         <asp:TextBox ID="TextBoxSearchName" runat="server" Width="200px" CssClass="InputText"></asp:TextBox>

   6:         <asp:Button ID="ButtonSearchName" runat="server" CssClass="SearchBtn" />

   7:         </div>

   8: </div>

In my codebind for my masterpage, I have the following:

   1: using System;

   2: using System.Web.UI;

   3: using System.Web.UI.WebControls;

   4: using ThreePLogic.Data.ThreePLogicAccess;

   5:  

   6: namespace ThreePLogic.Web.ASPWeb.ContactPages

   7: {

   8:     public partial class ContactMasterPage : MasterPage

   9:     {

  10:         public string SearchText

  11:         {

  12:             get

  13:             {

  14:                 TextBox textBoxSearch = Master.FindControl("ContentCenter").FindControl("TextBoxSearchName") as TextBox;

  15:                 if (textBoxSearch != null)

  16:                 {

  17:                     return textBoxSearch.Text;

  18:                 }

  19:                 else

  20:                 {

  21:                     return String.Empty;

  22:                 }

  23:                 

  24:             }

  25:         }

Then, in my page I derive from the masterpage I have the following.  Notice that I include the masterpage type so I can have type safe access to the public property.

   1: <%@ Master Language="C#" MasterPageFile="~/ContactPages/ContactMasterPage.Master"

   2:     AutoEventWireup="true" CodeBehind="ContactCompanyMasterPage.master.cs" Inherits="ThreePLogic.Web.ASPWeb.ContactPages.ContactCompany.ContactCompanyMasterPage" %>

   3:  

   4: <%@ MasterType TypeName="ThreePLogic.Web.ASPWeb.ContactPages.ContactMasterPage" %>

   5:  

   6: <asp:Content ID="Content1" ContentPlaceHolderID="GridContent" runat="server">

   7:  

   8:     <asp:Label ID="LabelSearchMirror" runat="server" Text=""   Visible="false" ></asp:Label>

Then, finally, in the codebehind, this is how I access my search box.  In my case, I assign it to an invisible label, then I can have server side presentation controls, like GridView, access it as a select parameter.

   1: using System;

   2: using System.Web.UI;

   3: using System.Web.UI.WebControls;

   4: using ThreePLogic.Common.Enums;

   5: using ThreePLogic.Web.ASPWeb.Code;

   6:  

   7: namespace ThreePLogic.Web.ASPWeb.ContactPages.ContactCompany

   8: {

   9:     public partial class ContactCompanyMasterPage : MasterPage

  10:     {

  11:         protected void Page_PreRender(object sender, EventArgs e)

  12:         {

  13:             GridViewCompany.PageIndex = UserService.I.GetCookieSelectedId(CookieIdType.CompanyCurrentPage);

  14:             if (!String.IsNullOrEmpty(Master.SearchText))

  15:             {

  16:                 LabelSearchMirror.Text = Master.SearchText;

  17:                 GridViewCompany.DataBind();

  18:             }

  19:         }

Good luck, and hope this helps!

I’m sure you can make a custom ControlParameter in ObjectDataSource to solve this, but I really don’t have time for that.  I just wanted something quick (which I now have and thought I’d share).

Basically, what I did was create an invisible label on my GridView that will get the string of values I want to retrieve, then, my ObjectDataSource gets one value (the string) and parses it into small values.  My plan is to do a quick run through of the code here, but then also post the project so you can see for yourself how it works.

Here we go.

First, let’s make a simple BusinessObject class that returns to us some data.  The basic object that will be returned is the Person defined as follows:

 public class Person

    {

        public Person()

        {

        }

        public Person(string _name, int _id)

        {

            this._name = _name;

            this._id = _id;

        }

        private string _name;

        private int _id;

        public string name

        {

            get { return _name; }

            set { _name = value; }

        }

        public int id

        {

            get { return _id; }

            set { _id = value; }

        }

    }

Next, we need two methods, the first is the method that does the heavy lifting (that is, takes a list of integers and returns the final list of people who have those cities in them, then, we need the method that polymorphically calls (did I spell that wrong, live writer thinks so… sorry) that method whose input is a single string.  That method parses the string (which was assembled in page_load of the calling page) and calls the first one.

So, here is the method ObjectDataSource actually calls to get it’s view of the data (remember, ObjectDataSource only returns one view).

 public List<Person> GetPeopleByCityList(List<int> cityList)

        {

            List<Person> personList = new List<Person>

                                          {

                                              new Person("Peter_SanJose", 1),

                                              new Person("Tom_Hartsdale", 2),

                                              new Person("Eric_Chicago", 3),

                                              new Person("Ron_SanJose", 1),

                                              new Person("John_Chicago", 3),

                                              new Person("Charly_Scarsdale", 4)

                                          };

            var personResult = from p in personList

                               where cityList.Contains(p.id)

                               orderby p.name

                               select p;

            return personResult.ToList();

        }

        public List<Person> GetPeopleByCityListString(string cityListString)

        {

            if (!String.IsNullOrEmpty(cityListString))

            {

                var values = cityListString.Split(';');

                var cityList = new List<int>();

                foreach (string s in values)

                {

                    cityList.Add(Convert.ToInt32(s));

                }

                return GetPeopleByCityList(cityList);

            }

            return null;

        }

    }

Now, the method that actually does the work.  Notice I’m using the C# 3.0 object initializer syntax to build it, but normally, you’d be calling a database or something like that here.  Also notice the clever LINQ that does the equivalent of an SQL IN clause.  That is, we’d normally be doing something like "Select .. From Person Where CityId IN (1,3..)).  It seems a little backwards to me, but it does the job.

So, now we have the business object, let’s put it to work.  Let’s build a simple aspx page that has a CheckBoxList, GridView,Label and a Button.  I’ll pre-populate the CheckBoxList just to keep my example simple.  Normally, you’d be getting that data from another data source like a database.

So, Here is the aspx file we built.

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title></title>

</head>

<body bgcolor="#00ccff">

    <form id="form1" runat="server">

    <div>

        <asp:Button ID="ButtonSearch" runat="server" Text="Retrieve" 

            onclick="ButtonSearch_Click" />

        <asp:Label ID="Label1" runat="server" Visible="false" Text="Label"></asp:Label>

        <asp:CheckBoxList ID="CheckBoxList1" runat="server">

            <asp:ListItem Value="2">Hartsdale</asp:ListItem>

            <asp:ListItem Value="4">Scarsdale</asp:ListItem>

            <asp:ListItem Value="3">Chicago</asp:ListItem>

            <asp:ListItem Value="1">San Jose</asp:ListItem>

        </asp:CheckBoxList>

        <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetPeopleByCityListString"

            TypeName="BO.BusinessObject">

            <SelectParameters>

                <asp:ControlParameter ControlID="Label1" Name="cityListString" PropertyName="Text"

                    Type="String" />

            </SelectParameters>

        </asp:ObjectDataSource>

        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 

            DataSourceID="ObjectDataSource1">

            <Columns>

                <asp:BoundField DataField="name" HeaderText="name" SortExpression="name" />

                <asp:BoundField DataField="id" HeaderText="id" SortExpression="id" />

            </Columns>

        </asp:GridView>

    </div>

    </form>

</body>

</html>

Notice that the asp controlparameter is passing the Label1 contents to the ObjectDataSource.  To load that, we need to put some code in the Page_Load event that will set that line.  Here is that code.  It simply reads the checkboxlist and builds the string of numbers (3,5,7,9.).

I’m pretty sure that is it.  Now, when you run the web site, you’ll get a screen that you can click multiple checkboxes on and get all the results that correspond with that checkbox.  Here is what it should look like:

Hope this Helps!  And, if you it the better way by making a custom ControlParameter, post it here and we can all ignore this article. 

So, I have to say one of my main motivations for doing posts is I enjoy helping others through problems.  It gives me a certain satisfaction to know that I have knowledge others may not at any give time and I have a great way to share that knowledge.  It also makes me feel good when others go out of their way to appreciate the effort.  I know when I post questions on forums and get good answers how happy I am, it’s good to know others appreciate my efforts.

So, continuing down that path, Here is the code necessary to answer Zimbran’s last question.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title>ODS DDL Example</title>

</head>

<body>

    <form id="form1" runat="server">

    <div>

        <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" 

            SelectMethod="GetMembers"

            TypeName="BusinessObject"></asp:ObjectDataSource>

        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 

               DataKeyNames="Id"

            DataSourceID="ObjectDataSource1">

            <Columns>

                <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True" 

                   SortExpression="Id" />

                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />

                <asp:BoundField DataField="Email" HeaderText="Email" SortExpression="Email" />

                <asp:TemplateField HeaderText="Approved" SortExpression="Approved">

                    <ItemTemplate>

                        <asp:Label ID="LabelYesOrNo" runat="server" 

                           Text='<%# (bool) Eval("Approved") ? "Yes" : "No"  %>'></asp:Label>

                    </ItemTemplate>

                </asp:TemplateField>

            </Columns>

        </asp:GridView>

    </div>

    </form>

</body>

</html>

The solution involves first dropping a GridView and ObjectDataSource onto your design surface in Visual Studio.  Then, using the little chevron on the GridView, choose edit columns and convert the column you are interested in making a DropDownList into a template.  From there replace the ItemTemplate with the DropDownList code below.  You get the code below.

<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title>ODS DDL Example</title>

</head>

<body>

    <form id="form1" runat="server">

    <div>

        <asp:ObjectDataSource ID="ObjectDataSource1" runat="server" SelectMethod="GetMembers"

            TypeName="BusinessObject"></asp:ObjectDataSource>

        <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="Id"

            DataSourceID="ObjectDataSource1">

            <Columns>

                <asp:BoundField DataField="Id" HeaderText="Id" ReadOnly="True" SortExpression="Id" />

                <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />

                <asp:BoundField DataField="Email" HeaderText="Email" SortExpression="Email" />

                <asp:TemplateField HeaderText="Approved" SortExpression="Approved">

                    <ItemTemplate>

                        <asp:DropDownList ID="DropDownListUser" runat="server" AutoPostBack="False" 

                            SelectedValue='<%# Bind("Approved") %>'>

                            <asp:ListItem Text="Yes" Value="True"></asp:ListItem>

                            <asp:ListItem Text="No" Value="False"></asp:ListItem>

                        </asp:DropDownList>

                    </ItemTemplate>

                </asp:TemplateField>

            </Columns>

        </asp:GridView>

    </div>

    </form>

</body>

</html>

And, when you run this code (assuming you have a simple business object that returns some data), you get this:

Hope this helps!