编辑Excel列

Question

using System;
using System.Data;
using System.Windows.Forms;
using System.Data.OleDb;
using System.IO;
using System.Text;


namespace SDM
{
public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
    }

    private void browsefiles_Click(object sender, EventArgs e)
    {
        if (openFileDialog1.ShowDialog()==DialogResult.OK)
        {
            display(openFileDialog1.FileName);
        }
    }

    private void display(string text)
    {
        textBox1.Text = string.Format("{0}", openFileDialog1.FileName);
    }

    private void importFile_Click(object sender, EventArgs e)
    {
        string PathConn = ("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + textBox1.Text + "; Jet OLEDB:Engine Type=5;Extended Properties=\"Excel 12.0;\"");
        OleDbConnection conn= new OleDbConnection(PathConn);

        OleDbDataAdapter myDataAdapter = new OleDbDataAdapter("Select * from [" + textBox2.Text+ "$]", conn);




        DataTable dt = new DataTable();

       myDataAdapter.Fill(dt);


        if (textBox2.Text.Contains("Life Group"))
        {
            dt.Columns.Add("Agent Code", typeof(string));
        }
        else if (textBox2.Text.Contains("Life Individual"))
        {
            DataColumn col = dt.Columns[9].ToString();
            String.Format("####-###");
           Console.WriteLine(col);

            myDataAdapter.Fill(dt);



        }

我正在尝试将Column [9]的格式从“1234567”更改为“1234-567”。我只是想在第4个数字之后添加一个短划线，但是在调用整个列进行更改时遇到了问题。任何人都可以提出任何建议吗？非常感谢。