How to change the value in a textbox to the previous value?

[Immortal49]

Hi,

I have two textboxes, value in textbox1 gets added to the value in textbox2 and i have this coding in place, the only problem i have is that if i made an error when adding a value in textbox1 and i remove the value to add the correct value the textbox2 value does not also change to the previous value so the calculations become wrong. My coding so far.

So ideally what i was looking for was help so when i remove the value in textbox1 or just change it to 0 then the original value is displayed in textbox2? hope that makes sense.

 

[Immortal49]

Coding is not appearing so i will paste it below

Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
Dim Value1, Value2 As Decimal

Decimal.TryParse(TextBox1.Text, Value1)
Decimal.TryParse(TextBox2.Text, Value2)

TextBox2.Text = (Value1 + Value2).ToString
End Sub

 

[Andrzejek]

Every time TextBox1'a Text Changes, the TextBox2's Text will change as well because that's what your last line of code does.

Have fun.

---- Andy

A bus station is where a bus stops. A train station is where a train stops. On my desk, I have a work station.

 

[Immortal49]

Thanks for your response, much appreciated.

 

[jebenson]

You need to store the original value of TextBox2 somewhere, so if TextBox1 is blanked or set to 0 you can restore the original TextBox2 value. I suggest using textBox2's Tag property:

Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged

TextBox2.Tag = TextBox2.Text

End Sub

Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
Dim Value1, Value2 As Decimal

If TextBox1.Text.Length = 0 Or TextBox1.Text = "0" Then
TextBox2.Text = TextBox2.Tag
End If

Decimal.TryParse(TextBox1.Text, Value1)
Decimal.TryParse(TextBox2.Text, Value2)

TextBox2.Text = (Value1 + Value2).ToString
End Sub

I used to rock and roll every night and party every day. Then it was every other day. Now I'm lucky if I can find 30 minutes a week in which to get funky. - Homer Simpson

Arrrr, mateys! Ye needs ta be preparin' yerselves fer Talk Like a Pirate Day!

 

[jebenson]

Oops, just realized that the above code won't work, because changing textbox1 will change textbox2, which will change the Tag value as well. You will need something like a global flag that you set when textbox1 is being changes, so you don't change textbox2's Tag value:

Dim bText1Changing As Boolean = False 'declare this at the top of the form, in Declarations

Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged

If Not bText1Changing then
TextBox2.Tag = TextBox2.Text
End If

End Sub

Private Sub TextBox1_TextChanged(sender As Object, e As EventArgs) Handles TextBox1.TextChanged
Dim Value1, Value2 As Decimal

bText1Changing = True

If TextBox1.Text.Length = 0 Or TextBox1.Text = "0" Then
TextBox2.Text = TextBox2.Tag
End If

Decimal.TryParse(TextBox1.Text, Value1)
Decimal.TryParse(TextBox2.Text, Value2)

TextBox2.Text = (Value1 + Value2).ToString

bText1Changing =False

End Sub

I used to rock and roll every night and party every day. Then it was every other day. Now I'm lucky if I can find 30 minutes a week in which to get funky. - Homer Simpson

Arrrr, mateys! Ye needs ta be preparin' yerselves fer Talk Like a Pirate Day!