Question

I am trying to display a TextChanged result but I have an error that says:

An unhandled exception of type 'System.FormatException' occurred in mscorlib.dll Additional information: Input string was not in a correct format.

Here is my sample code:

Public Class Form1
Dim double1 As Double = 0.0
Dim double2 As Double = 0.0
Dim result As Double = 0.0
Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs) Handles TextBox2.TextChanged
    double1 = TextBox1.Text
    double2 = TextBox2.Text
    result = Double.Parse(Label1.Text).ToString

    result = double1 + double2
End Sub

I am new to this stuff. How will I fix this? Thank you for the response.

Answer 1

您可以同时使用“IF”或val来解决问题。而且你没有在标签上显示任何东西。你需要它＆gt; Label1.text = result展示它。

Public Class Form1

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

        'If Not IsNumeric(TextBox1.Text) OrElse Not IsNumeric(TextBox2.Text) Then Exit Sub

        Dim double1 As Double
        Dim double2 As Double
        Dim result As Double

        double1 = Val(TextBox1.Text)
        double2 = Val(TextBox2.Text)

        result = double1 + double2
        Label1.Text = result

    End Sub

End Class

How to add Double.Parse

1 个答案: