How to import data from excel to textbox?

I am trying to import data from Excel to textbox.

I want import data from Excel saved on my C: disk and i get error with System.NotImplementedException I use library for Excel and Office.

Dim ExcelApp As New Excel.Application
Dim ReteilerWorkbook As New WindowsApp1.ExcelApp.Workbooks.Open("C:\Users\TR\1.xlsx")
Dim retailerWorksheet As New RetailerWorkbook.Sheets(1)

Private Sub ZPlikuToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ZPlikuToolStripMenuItem.Click

    Me.TextBox1.Text = ""
    TextBox1.Text = retailerWorksheet.cells(1, 1).text
End Sub    

I want fill textbox1 with data from cell A1

Here's what I do on VB.NET to import data from Excel:

First, I import Interop on the head of my VB module:

Imports Excel = Microsoft.Office.Interop.Excel

Then I declare the following INSIDE the routine:

Private Sub ...
    Dim ExcelApp As Excel.Application = New Excel.Application
    Dim ReteilerWorkbook As Excel.Workbook = ExcelApp.Workbooks.Open("C:\Users\TR\1.xlsx")
...

Could you try it this way?

To retrieve the cells(1,1) content you don't need to declare the Worksheet. It doesn't compensate the effort. So you could do this simply with:

TextBox1.Text = ReteilerWorkbook.Sheets(1).Cells(1,1).Text

And, as always, don't forget to close the workbook at the end:

ReteilerWorkbook.Close()