ansaurus

Question

Answer 1

A:

First you have to build your select statement

Select [ID], [Value] From [Table]

You would store your query into a variable (I use "r" for return) Then you need to attach it to the dropdown

DropDownList1.DataTextField = r.Value
DropDownList1.DataValueField = r.ID
DropDownList1.Databind()

If you really REALLY need to loop, then try something along these lines (not code is not checked, just a general idea.)

For Each o as object in r
  DropDownList1.Items.Insert(o.ID,new ListItem(o.Value,o.ID))
Next

Or with the DataReader (again, untested, but prolly close)

While DataReader.Read()
  DropDownList1.Items.Insert(datareader("value"),new ListItem(datareader("name"),datareader("value"))
End While

rockinthesixstring 2010-02-27 05:55:19

ugio 2010-02-27 05:59:18

I would recommend NOT looping if you don't have to. Databind is more efficient.

rockinthesixstring 2010-02-27 06:05:23

well i have numerous records that come from the database depending on the sql query, so i thought looping with while in a datareader was the right thing to do. so is there no solution but to change the code, or can i work with my existing loop?

ugio 2010-02-27 06:08:42

see my edit above. It's prolly not bang on since I'm not sitting in front of a IDE, but it's close.

rockinthesixstring 2010-02-27 06:13:05

Another option might be to loop through your records and add them to your own custom object, then bind your DropDownList to the custom Object.

rockinthesixstring 2010-02-27 06:13:56

see i did that. dropdownlist.items.add(datareader("name","value")and the result i got was Black1, blue2 ... as concatenated

ugio 2010-02-27 06:17:35

I used Items.Insert, not Items.Add. You also need to add it DropDownList1.Items.Insert(datareader("value"),new ListItem(datareader("name"),datareader("value"))... or something like that

rockinthesixstring 2010-02-27 06:20:26

o man ur right. thanks for being patient man.

ugio 2010-02-27 06:22:58

don't forget to mark as answer ;)

rockinthesixstring 2010-02-27 06:23:49

done. thats one more feather in ur cap

ugio 2010-02-27 06:25:57

getting close to my 1000 goal... shootin for the end of the weekend ;)

rockinthesixstring 2010-02-27 06:26:37

how do i become better in vb.net? i need to work on it evreyday, so i wanna be really good at it

ugio 2010-02-27 06:29:15

It all depends on how deep you want to go. If this is a career and your full time job... you'll prolly want to go to school. If you want to do it on your own... Google is your friend. Come up with an idea or a challenge and work your way through it.

rockinthesixstring 2010-02-27 06:37:57

Answer 2

A:

Assuming that you have an IList implementation which you are binding the data objects to (you seem to have the results materialized in something already, as you say you can populate the text), what you need to do is specify the name of the property/member on your instances returned from your IList implementation.

So, assuming that you have a DataTable with columns of ID and Value, or an IList of objects that was populated from LINQ-to-SQL/Entities, each with an ID property and a Value property, you would do this:

DropDownList1.DataValueField = "ID"
DropDownList1.DataTextField = "Value"

You need to set it to the names of the fields as opposed to the values, as the binding mechanism uses the property descriptor framework to figure out how to map those strings to the properties/columns which contain the data.

casperOne 2010-02-27 06:11:29

ansaurus

tags:

views:

answers:

populating dropdown list in vb.net

related questions