Automatically update textbox values from combobox changes

[smchoudhury]

Hi Guys,
Can someone direct me on how can i automatically update my value when a user changes the combobox item. At the moment i have a button click when the user changes the combobox item and press the button the values get updated, everytime the combobox item get changed i have to repeat it click the button to update the value. I want something where automitically as soon as the combobox item selected the total value in the text box to change without clicking the button. So if a user changes the item slected from the combobox the values within the text box should changes accoding to combobox changes without a button event handler:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If ComboBox1.SelectedItem = "Seafood" Then
TextBox1.Text = 3.5 * ComboBox2.SelectedItem
End If

End Sub

Thanks,
choudhmh

 

[Andrzejek]

So what do you get when you multiply

[tt]3.5 * ComboBox2.SelectedItem [/tt] ???

What does your [tt]TextBox1.Text[/tt] show?

Have fun.

---- Andy

 

[smchoudhury]

the combobox items are 1-10, which ever one i selected it does times it by 3.5 but for the answer to appear inside the textbox i have to press the button handler. What i want is to put htis code inside the combobox event handler and everytime a user changes the item (1-10) the calulation should be done atomatically without the need for pressing the button. I need a code that will perform that function....

 

[Andrzejek]

How about:

    Private Sub Form1_Load(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles MyBase.Load
[blue]
        For i As Integer = 1 To 10
            ComboBox1.Items.Add(i)
        Next
[/blue]
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
[blue]
        TextBox1.Text = 3.5 * ComboBox1.SelectedItem
[/blue]
    End Sub

Have fun.

---- Andy

 

[smchoudhury]

I'm using Windows FORM not normal web format vb.net. I do not have Form1_Load instead its the classical
Public Class Form1
End class
I cannot put the code inside there. it throws an error, if i put the code provided inside a button event handler then this code work perfectly but again i dont want a button to control things instead the value should be updated automatically.

Thanks

 

[smchoudhury]

Sorry it works actualyy...tgis is what i did with your code:

Public Class Form1

Private Sub Form1(ByVal sender As System.Object, _
ByVal e As System.EventArgs) Handles MyBase.Load

For i As Integer = 1 To 10
ComboBox1.Items.Add(i)
Next

End Sub

and it seem to produce the function i need.

Thanks

 

[smchoudhury]

Using this code you provided with the amendment i made now my form design is not showing up. this is the error i recive:

at Microsoft.VisualStudio.Shell.Design.Serialization.CodeDom.CodeDomEventBindingService.ValidateMethodName(String methodName)
at System.ComponentModel.Design.EventBindingService.EventPropertyDescriptor.SetValue(Object component, Object value)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeAttachEventStatement(IDesignerSerializationManager manager, CodeAttachEventStatement statement)
at System.ComponentModel.Design.Serialization.CodeDomSerializerBase.DeserializeStatement(IDesignerSerializationManager manager, CodeStatement statement)


any idea how i could go about fixing this problem.....

 

[Andrzejek]

I don't know what to tell you...

I just started a new VB.NET Project in VS 2008. That gives me one empty Windows Form named Form1. I placed a TextBox1 and a ComboBox1, and then pasted this code:

Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, _
           ByVal e As System.EventArgs) Handles MyBase.Load
        For i As Integer = 1 To 10
            ComboBox1.Items.Add(i)
        Next
    End Sub
    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, _
        ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        TextBox1.Text = 3.5 * ComboBox1.SelectedItem
    End Sub
End Class

It works and runs just fine....

Have fun.

---- Andy