Here is what my code looks like:

```
private void exportToExcelButton_Click(object sender, EventArgs e)
{   
    txtBox.Clear();

    txtBox.AppendText("Beginning Export...");
    ExportExcel(txtBox);
    txtBox.AppendText("Export complete...");                  
}

```

The problem I am having is that whenever the button is clicked (to execute the function above), only part of the current text in the TextBox (`System.Windows.Forms.TextBox`) is cleared, and replaced with the first line: "Beginning Export ...".
However once the function `ExportExcel(txtBox)` is done executing, *then* the entire text is replaced by the new one generated in `ExportExcel(txtBox)`.

Inside `ExportExcel(txtBox);` I have several `txtBox.AppendText()` statements explaining to the user the actions being made.

I have tried clearing the text with `txtBox.Text = String.Empty;` and `txtBox.Text = "";`and neither have worked.

Let me know if anything needs to be clarified, thanks.