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can I bind my arralist to a datalist?

Posted on 2007-11-29
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Last Modified: 2012-05-05
hi there,
Im trying to output an arraylist using a datalist.  I have tried the following although this fails..

    <ItemTemplate>
        <%# DataBinder.Eval(Container.DataItem, "_options")%>
    </ItemTemplate>

The complication I have that I cant get around is that the arraylist is a property of my custom built class.  Therefore I have the following structure (included within the code snippet part) which I bind to using the following

        DataList1.DataSource = results._options;
        DataList1.DataBind();

Problem I have is that I dont know what to put within the markup, denoted below with the triple x to output the elements within the arraylist!

<li><%# DataBinder.Eval(Container.DataItem, "xxx") %></li>

Please tell me how!

With this working I expect to get the following html

<li>Terry</li>
<li>Jane</li>
<li>Tim</li>

If I was to do the following

_options.add("terry");
_options.add("Jane");
_options.add("Tim");


Thanks


public class results
{
    public string _title;
    public ArrayList _options = new ArrayList();
 
	public results()
	{
	}
}

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Question by:jimbona27
  • 8
  • 3
11 Comments
 
LVL 6

Accepted Solution

by:
Roopesh_7 earned 350 total points
ID: 20375585
do like this

class myClass
{
public string _name;

public myClass(string name)
{
_name = name;
}

public string Name
{
get
{
return _name;
}
}

<aspataList id="DataList1" runat="server">
<ItemTemplate>
<%# DataBinder.Eval(Container.DataItem,"Name") %>
</ItemTemplate>
</aspataList>

public class test : System.Web.UI.Page
{
protected System.Web.UI.WebControls.DataList DataList1;

private void Page_Load(object sender, System.EventArgs e)
{
ArrayList al = new ArrayList();
al.Add(new myClass("Peter"));
al.Add(new myClass("Mary"));

DataList1.DataSource = al;
DataList1.DataBind();
}
}


0
 

Author Comment

by:jimbona27
ID: 20388153
yeah great, this is pretty much what i've been doing, creating objects which is always a good thing anyway...

although what your doing different to me is

al.Add(new myClass("Peter"));

whereas i've used datalists with a datatable behind it to get around it, not knowing you can do what you've done here.
i'll try it on monday to know for sure whether it works for me.
thanks in the meantime.

0
 

Author Comment

by:jimbona27
ID: 20396491
i've changed my code now but how do I refer to the property within the markup, like so

<%# DataBinder.Eval(Container.DataItem, "xxx") %>

I've tried


<%# DataBinder.Eval(Container.DataItem, "Name") %>

although this fails:
 Exception Details: System.Web.HttpException: DataBinding: 'classname' does not contain a property with the name 'Name'.

Note: The Name is a public variable within the object like below:



public class test
{
    public string _Name;
    ....
 
}

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LVL 6

Expert Comment

by:Roopesh_7
ID: 20396567
could you please sent whole code in cs. B'cos its working here
0
 

Author Comment

by:jimbona27
ID: 20396593
i've seen this online but fails for me:

<%#  ((System.Collection.ArrayList)DataBinder.Eval(Container.DataItem, "[\"myarraylist\"]") )[0] %>
0
 

Author Comment

by:jimbona27
ID: 20402003
does this help?
the error message I get:

 DataBinding: 'test does not contain a property with the name '_username'.

thanks
// code that creates the arraylist
 
        ArrayList options = new ArrayList();
 
        while (reader.Read())
        {
            options.Add(new test((Int32)reader["id"],(string)reader["username"],(string)reader["address"]);
        }
 
...
 
// the bind
 
        datalist1.DataSource = db.GetData();
        datalist1.DataBind();
 
 
// markup
 
<%# DataBinder.Eval(Container.DataItem, "Username") %>
 
 
 
// the class
 
 
public test
{
    public Int32 _id;
    public string _a;
    public string _b;
    public string _c;
 
    public comment()
    {
    }
	public comment(Int32 a, string b, string c)
	{
        _a = a;
        _b = b;
        _c = c;
	}
 
}

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Author Comment

by:jimbona27
ID: 20402005
sorry markup should read

<%# DataBinder.Eval(Container.DataItem, "_username") %>
 
0
 

Author Comment

by:jimbona27
ID: 20402313
think i got it.
you have to have a method to return the property of the object to use in the markup.
i was just using the public property itself.
0
 

Author Comment

by:jimbona27
ID: 20402404
how do i get access to the properties in the code behind file?

so i have an arraylist of cars

i.e.
        cars test = new cars();
        test = (cars)myfunctiion();  // cast the return arraylist into car objects -- fails

i can kinda see why but I dont know how to do it.

i want to access the 'id' property within my object,

something probably along this line although it fails for me:

response.write(myarraylist.row[0].column[1]);

writes "hello"


// creating the arraylist with objects
 
public arraylist myfunctiion()
{
        ArrayList test = new ArrayList();
 
        while (reader.Read())
        {
            
            test.Add(new cars("10","hello");
        }
 
        return test;
}

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0
 

Author Comment

by:jimbona27
ID: 20402448
got it.
0
 
LVL 6

Expert Comment

by:Roopesh_7
ID: 20403189
Good...I just wait for you...:) you are on the right track
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