How to find attribute for specific element?

QuadFather · April 7th, 2010, 12:33 PM

I'm programming in VB, using Visual Studio 2008.
This is a Windows Forms program.

GOAL: I want TextBox1 to display the <Calories> for the <Food> that matches the contents of ComboBox1 when I press Button1.

Objects I'm using:

ComboBox1
TextBox1
Button1

Here is my xml file (Foods.xml):

Code:

<?xml version="1.0" encoding="utf-8"?>
<Foods>
  <Food>
    <Name>BigMac (McDonald's)</Name>
    <Calories>485</Calories>
    <Fat>21.5</Fat>
  </Food>
</Foods>

Code I've tried:

Code:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim FoodCalories
        FoodCalories = XElement.Load("Foods.xml").<Food>.<Name>(ComboBox1.Text).<Calories>
        TextBox1 = FoodCalories
    End Sub

Doesn't work.

Please help!

Martin Honnen · April 7th, 2010, 12:41 PM

You need to spend some hours on the LINQ to XML documentation; it is online at http://msdn.microsoft.com/en-us/library/bb387098.aspx but of course your Visual Studio documentation has the same section too, only accessible faster.

Code:

Dim food As XElement = XElement.Load("Foods.xml").<Food>.FirstOrDefault(Function(f) f.<Name>.Value = ComboBox1.Text)
If food IsNot Nothing Then
  TextBox1.Text = food.<Calories>.Value
Else
  ' treat the case here that no food was found
End If