multi column database source for drop down list

mii2029 · April 8th, 2008, 10:54 PM

I have a dependent drop down list that needs to be populated by every column in a row, but NOT concatenated. Each column in the row needs to be a separate list item. There has got to be an easy way to do this without writing 15 pages of code.

Does anyone know how to do this? I'm using VWD and Visual Basic to build the webpage. I've spent a week searching for an answer and I am ready to throw the computer through the wall I'm so frustrated with this problem.

Thanks,

dparsons · April 9th, 2008, 07:26 AM

Hmm. This seems like an odd request.

Databinding directly to your datasource is going to be out of the question since, as you probably know, you can only bind to 2 columns within a DataSource. (DataTextField and DataValueField)

What you are probably going to have to do is some logic such as this

Code:

For Each dr As DataRow in dt.Rows
    For Each dc as DataColumn in dt.Columns
        dropDownList1.Items.Add(new ListItem(Convert.ToString(dr[dc]), Convert.ToString(dr[dc])))
    Next
Next

This code will iterate through each Row in your data source and then iterate through each column in each row of the datasource (here i have assumed that dt is of type DataTable). Is this what you are looking for?

hth.

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mii2029 · April 12th, 2008, 09:24 PM

Your code got me close, but I'm struggling with the last piece of the puzzle. Let me lay out the tables and the desired operation:

Table 1 (tied to dropdownlist1)
Id Chapter
1 21
2 22
3 23

Table 2 (tied to dropdownlist2)
Id Section1 Section2 Section3
1 11 21 31
2 12 22 32
3 13 23 33

The tables are a lot larger, but this gives you an ideas of how they're set up. The way this is supposed to work is the user selects a Chapter from dropdownlist1. This part works fine. Then, based on the the selected chapter dropdownlist2 is populated with a list of each section in the matching Id row as a separate item in the dropdownlist. The user then selects a Section from dropdownlist2. Getting dropdownlist2 to populate properly is what I can't seem to get right.

I'm trying to convert a macro to a web-based application, and for this functionality I used Select case and With statements to populate the two dropdownlists. I was hoping to use a database to store all of the variables instead of writing 200 lines of code. I'm still playing with your code to get this to work, but so far no dice.

Thanks for your input!

murshed · August 4th, 2008, 05:05 PM

Hi,
I might be a bit clueless here (no real surprise, given that I'm a complete novice), but I'm wondering if you couldn't just have the first table's Id be passed on to a dynamic select statement to generate table 2 as and when needed?

I do something similar with a couple of dropdown lists in classic asp, from what I've understood of your problem.
or you might even use AJAX and send the result of table1 dropdown to the server immediately after the user selects an option, then have code waiting to repopulate the same dropdown box with the sections information.

I don't know, I might be missing the complexity of it.