converting integer to decimal values while adding both - vb.net

Question

I am working on a vb.net application.
My code is the following:
txtTotalPrevious.Text = Val(txtTotalPrevious.Text) + Val(txtoldtotal.text)
my values are:
txtTotalPrevious.Text=187.0000
txtoldtotal=3
I get the result
result =190
but my expected result is:
result=190.0000
What is the issue in my logic?

Answer 1

You can use String.Format if you want to output string be like you want:
Dim str1 As String = "187.0000"
Dim str2 As String = "3"
Dim resultString As String = String.Format("{0:0.0000}", Val(str1) + Val(str2))
' And the result will be 190.0000
And if you want the double result:
Dim resultDouble as Double= Val(str1) + Val(str2)
' And the result will be Double 190
EDIT
Based on varocarbas comments you should consider some notes:
Avoid using Val method
The Val function stops reading the string at the first character it
cannot recognize as part of a number. Symbols and characters that are
often considered parts of numeric values, such as dollar signs and
commas, are not recognized. However, the function recognizes the radix
prefixes &O (for octal) and &H (for hexadecimal). Blanks, tabs, and
linefeed characters are stripped from the argument.
The following call
returns the value 1615198.
Val(" 1615 198th Street N.E.")
The Val function recognizes only the period (.) as a valid decimal
separator. When different decimal separators are used, as in
international applications, use CDbl or CInt instead to convert a
string to a number. To convert the string representation of a number
in a particular culture to a numeric value, use the numeric type's
Parse(String, IFormatProvider) method. For example, use Double.Parse
when converting a string to a Double.
As a VB.Net Programmer use & instead of + for string concatenation
When you use the + operator, you might not be able to determine
whether addition or string concatenation will occur. Use the &
operator for concatenation to eliminate ambiguity and to provide
self-documenting code.