CODEWITHSUNDEEP
vb.netwinformscombobox
Criel
Criel

Reputation: 815

Load comboboxes with one line of code?

I have around 15 comboboxes on my form, all being loaded with the same information pulled from a table(~150 entries). Currently I am taking the information from the table, then looping through the entries and adding them to each textbox. I'm wondering if there's a more efficient way to load these comboboxes then having to individually add the table entry into each combobox, having to list 15 lines of code within the For loop.

I'm not seeing any performance issues with this, but figured I might as well work with the most efficient way possible rather than stick with what works. :)

Upvotes: 2

Views: 308

Answers (3)

matrixanomaly
matrixanomaly

Reputation: 6947

You could also do it this way since you mentioned that you already have a table.

  1. Use a datatable

Change your table object into a datatable, which will assist in binding to the comboboxes. It might help if you add the datatable to a dataset too. That way you can attach all ComboBoxes (which are UI elements that let users see information) to the same DataSource, which is the datatable, in the dataset.

  1. Binding

Now all you need to do is loop through all the comboboxes and set the datasource to the same table, that is if you decide to do it programmatically like so:

ComboBox1.DataSource = ds.Tables(0)
ComboBox1.ValueMember = "au_id"
ComboBox1.DisplayMember = "au_lname"

A further tutorial on this with the example above is found here

You can then also get the user selected value with ComboBox1.selectedValue.

On the other hand, if you did this with C# WPF, you can bind each comboBox in the XAML directly, I am unsure if this can be done in VB.net as I tried to look for the option but did not manage to do so, something you might want to try though.

Some very useful tutorials and guides on Data binding, which you might be interested:

~ denotes recommended reading for your question

MSDN: Connect data to objects

DotNetPerls on DataGridView (note this isn't a combobox, just displaying values)

~ VBNet DataTable Usage from DotNetPerls (this is in relation to 1.)

~ SO Q&A on Binding a comboBox to a datasource

Concepts of Databinding

Upvotes: 2

Btc Sources
Btc Sources

Reputation: 2041

Since Combobox items are a collection, if their elements are the same, you can build and array with the objects you want to insert, and then just insert this array to each ComboBox with the method AddRange() (it's a method which exists inside the Combobox.items).

Getting an example from MSDN:

Dim installs() As String = New String() {"Typical", "Compact", "Custom"}
ComboBox1.Items.AddRange(installs)

Then you would only have to do a loop to add the array to each ComboBox. Of course, you will need to build your array first on your own, instead of this easy string array from the example.

Reference:

MSDN - AddRange

Upvotes: 2

Steven Doggart
Steven Doggart

Reputation: 43743

You can create a list of the combo boxes, and then just loop through them. For instance:

Dim cbos() As ComboBox = {ComboBox1, ComboBox2, ComboBox3}
For Each cbo As ComboBox In cbos
    ' Load cbo from table
Next

Alternatively, if they are named consistently, you could find the combo box by name:

For i As Integer = 1 to 15
    Dim cbo As ComboBox = DirectCast(Controls("ComboBox" & i.ToString())), ComboBox)
    ' Load cbo from table
Next

Upvotes: 5

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