Rename column header name in ASP.Net GridView with AutoGenerateColumns property set to True

Here I have created sample that will help you out.

HTML

<div>
    <asp:GridView ID="gvData" runat="server" AutoGenerateColumns="true" />
    <br />
    <asp:Button Text="Change Column Name" runat="server" OnClick="ChangeName" />
    <br />
    <br />
    <asp:GridView ID="gvRenameData" runat="server" AutoGenerateColumns="true" />
</div>

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[3] { new DataColumn("A"),
                                        new DataColumn("B"),
                                        new DataColumn("C")
        });

        dt.Rows.Add("abc", "bbc", "ccc");
        dt.Rows.Add("xyz", "yyz", "zzz");
        ViewState["Data"] = dt;
        gvData.DataSource = dt;
        gvData.DataBind();
    }
}

protected void ChangeName(object sender, EventArgs e)
{
    DataTable dt = null;
    if (ViewState["Data"] != null)
        dt = (DataTable)ViewState["Data"];
    gvRenameData.DataSource = RenameDataTableColumn(dt, "1", "2", "3");
    gvRenameData.DataBind();
}

public static DataTable RenameDataTableColumn(DataTable sourceDataTable, params string[] names)
{
    if (names.Length > sourceDataTable.Columns.Count)
    {
        throw new IndexOutOfRangeException("names parameter count must be equal or less than sourceDatatable column count");
    }
    for (int i = 0; i < names.Length; i++)
    {
        sourceDataTable.Columns[i].ColumnName = names[i];
    }
    return sourceDataTable;
}