Removing unnecessary 0's from an array? " InvalidCastException was unhandled"

[rosleenXOXO]

I have an array with a possible of 25 numbers that can be entered into it, i need help figuring out how to take out the unnecessary zero's for the valueas i have not entered into my array.

Public Class Form1
   
  Dim mintArray() As Integer 'Declares Array without giving it a size
  Dim Array(24) As Integer
  Dim J As Integer = 0


Private Sub btnPutNumberIntoArray_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnPutNumberIntoArray.Click

        Array(J) = CInt(txtNumbers.Text)
        J = J + 1
        txtNumbers.Clear()
        txtNumbers.Focus()

    End Sub

Private Sub btnDisplayNumbersInArray_Click_1(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisplayNumbersInArray.Click
        Static J As Integer
        ReDim Preserve mintArray(J)
        'Gives Array a size and preserves the array values
        mintArray(J) = CInt(txtDisplayNumbers.Text)
        J = J + 1
        txtDisplayNumbers.Clear()

        'DISPLAYS THE CONTENTS OF ARRAY.
        For I = 0 To J - 1
            'Accumulates values in Textbox2 and displays these values.
            txtDisplayNumbers.Text = txtDisplayNumbers.Text & CStr(mintArray(I)) & ControlChars.NewLine
        Next
        txtDisplayNumbers.Clear()
        txtDisplayNumbers.Focus()

        For J = 0 To 24
            txtDisplayNumbers.Text = txtDisplayNumbers.Text & CStr(Array(J)) & ControlChars.NewLine
        Next
    End Sub 

End Class

I get an error at the highlighted part : " InvalidCastException was unhandled, Conversion from string "" to type 'integer' is not valid."