sql c＃删除div id的语法

Question

Hey guys I have a delete button tied to some Javascript like so:

    <script type="text/javascript">
    function confirm_delete()
{
  if (confirm("Are you sure you want to delete this comment?")==true)
    return true;
  else
    return false;
}
</script>
<p>
<asp:Button ID="btn" OnClientClick="if(confirm_delete()){/* post back*/}else{return false;};" OnClick="btnDelete_Click" runat="server" Text="delete"/>

In the code behind I have this:

      using (OdbcCommand cmd = new OdbcCommand("SELECT idWallPosting, wp.WallPostings, p.PicturePath FROM WallPosting wp LEFT JOIN User u ON u.UserID = wp.UserID LEFT JOIN Pictures p ON p.UserID = u.UserID WHERE wp.UserID=" + userId + " ORDER BY idWallPosting DESC", cn))
            {
                using (OdbcDataReader reader = cmd.ExecuteReader())
                {
                    test1.Controls.Clear();

                    while (reader.Read())
                    {

                        System.Web.UI.HtmlControls.HtmlGenericControl div = new System.Web.UI.HtmlControls.HtmlGenericControl("div");
                        div.Attributes["class"] = "test";


                        div.ID = String.Format("{0}", reader.GetString(0));
                        // the Div ID is set to my idWallPosting in my WallPosting Table
                        Image img = new Image();
                        img.ImageUrl = String.Format("{0}", reader.GetString(2));

                        img.AlternateText = "Test image";

                        div.Controls.Add(img);
                        div.Controls.Add(ParseControl(String.Format("&nbsp&nbsp " + "{0}", reader.GetString(1))));
                        div.Attributes.Add("onclick", "return confirm_delete();");

                        div.Style["clear"] = "both";
                        test1.Controls.Add(div);

                    }
                }
            }
        }
    }


protected void btnDelete_Click(object sender, EventArgs e)
{

    //serverside code if confirm was pressed to delete from WallPosting table based on Div ID.

}

The first part of the code behind dynamicallys adds divs and adds the id = to idWallPosting I thought I should do this so when it came to delete them, all I had to do was refrence the div.ID but im unsure how to add in a string to convert the div id to string so I can pass that to my sql syntax?

This has to be taken from the html side not from server side the output of which looks like this when the divs are loaded on execution:

(firebug)

<div id="ctl00_ContentPlaceHolder1_ContentPlaceHolder2_26"><div>

How would I strip of the ct100 contentplaceholder etc etc to get the very end number (26) and place that in my delete button as a string?

EDIT: (Patrick)

protected void btnDelete_Click(object sender, EventArgs e)
{
    idWallPosting = Div.ID;

    //serverside code if confirm was pressed.
        using (OdbcConnection cn = new OdbcConnection("Driver={MySQL ODBC 3.51 Driver}; Server=localhost; Database=gymwebsite2; User=root; Password=commando;"))
        {
            cn.Open();
            using (OdbcCommand cmd = new OdbcCommand("DELETE FROM WallPosting WHERE idWallPosting = "+idWallPosting+")", cn))
            {
                cmd.ExecuteNonQuery();
            }
        }
        PopulateWallPosts(); //error here

}

Edit:

protected void btnDelete_Click(object sender, EventArgs e)
{

    string id = "ctl00_ContentPlaceHolder1_ContentPlaceHolder2_26";
    string[] idFragments = id.Split('_');
    id = idFragments[idFragments.Length - 1];

    //serverside code if confirm was pressed.
        using (OdbcConnection cn = new OdbcConnection("Driver={MySQL ODBC 3.51 Driver}; Server=localhost; Database=gymwebsite2; User=root; Password=commando;"))
        {
            cn.Open();
            using (OdbcCommand cmd = new OdbcCommand("DELETE FROM WallPosting WHERE idWallPosting = " + id + ")", cn))
            {
                cmd.ExecuteNonQuery();
            }
        }
        //PopulateWallPosts();

}

Does nothing.

Answer 1

If you are sending the div back to the server side as a control.. which is what it looks like you are trying to do (forgive me if I'm wrong)

From what it looks like you are setting the divs up so that when you click on them... it asks for confirmation before deletion?

so every time you click on a div you are expecting a post back?

Just to throw this out there... but you would be much better off using jquery and making an ajax call.

Update

You could possibly use a hiden control...

<input id="tsIdValue" type="hidden" runat="server" />

then server side you can get the value from your hidden control by using

tsId = tsIdValue.value;

When you build your div and you call the confirm_delete method you might be able to do:

div.Attributes.Add("onclick", "return confirm_delete(this.id);"); 

When you click on the div... you would want to set the value of the hidden control to the id of the div via javascript.

 function confirm_delete(id)

    {
      if (confirm("Are you sure you want to delete this comment?")==true)
        tsIdValue.value = id;
        return true;
      else
        return false;
    }

You would still have to have javascript cause the post back using the __doPostBack() call

Answer 2

So when div is clicked you want to delete or you want to delete upon button click only?

If it is just button click then you can use CommandArgument to pass your id.

If it is div click then again you need to pass the id to your confirm_delete to get refrence.

Edit:1

Looking at your code and comments there is no other way but to do an ajax postback because clicking on div isn't going to trigger postback by default like asp.net button. And you want to execute the Button_Click event of div click which isn't right as well.

Although I don't see a good idea to have delete upon the entire div. It will be very annoying if users accidentally click on div and the message pops up.

Edit 2:

Here is a sample if that helps:

<div id="testdiv" runat="server">Hello world</div>

//Pass record id to your confirm_delete
int id = 10;
testdiv.Attributes.Add("onclick", "return confirm_delete(" + id.ToString() + ");");

//Updated confirm_delete function

<script type="text/javascript">
        function confirm_delete(id){
            if (confirm('Are you sure you want to delete?')) {
                __doPostBack('DivClicked', id);
            }
            else {
                return false;
            }
        }
</script>


//This goes in your Page_Load code-behind
            if (Page.IsPostBack)
            {
                //It is a postback so check if it was by div click
                string target = Request["__EVENTTARGET"];
                if (target == "DivClicked")
                {
                    string id = Request["__EVENTARGUMENT"];
                    //Call you delete function passing record id
                    Response.Write(id.ToString());
                }
            }

Answer 3

With ASP.Net (before .net 4.0) it will auto append some stuff to the beginning of the id to ensure that it is unique. So in short you won't be able to get rid of this entirely but you can split out the relevant part of your Id for use in you sql query. I would do this like so:

 //Note this is just for demonstration purposes you will need to actually get the Id of 
 //Id the control here
 string id = "ctl00_ContentPlaceHolder1_ContentPlaceHolder2_26";
 string[] idFragments = id.Split('_');
 id = idFragments[idFragments.Length - 1];

This splits the Id string on the underscore character then returns the last element in the resulting array. You can then use this in your sql query.