找到解决方案，只需要做一个数据库....这是工作代码：

  else if（e.CommandName ==Delete） 
 {
 int index = Convert.ToInt32（e.CommandArgument）; 
 GridView1.DeleteRow（index）; 
（（DataTable）ViewState [DataTable]）。Rows [index] .Delete（）; 
（（DataTable）ViewState [DataTable]）。AcceptChanges（）; 
 GridView1.DataSource =（DataTable）ViewState [Data]; 
 GridView1.DataBind（）; 
} 
 

I'm trying to delete a row in a gridview (the data is not in the database yet), so it should be a simple delete row, if anybody can please point me in the right direction.... This is what I have done:

     else if (e.CommandName == "DeletePart")
    {
        int index = Convert.ToInt32(e.CommandArgument); //#1 line
        GridView1.DeleteRow(index);  //#2 line
    }

The error that I am receiving is : "Input string was not in a correct format." (this happens on #1 line)...

This is how the gridview looks like: (use a linkbutton to do the delete)

    <asp:GridView ID="GridView1" runat="server"  AllowPaging="True" 
                                EmptyDataText="No parts has been added to the model, please add a part."
                                BorderColor="Black" BorderStyle="Solid"  BorderWidth="2px" 
                                CellPadding="3" onrowcommand="GridView1_RowCommand" 
                            onrowediting="GridView1_RowEditing" onrowdeleting="GridView1_RowDeleting">
                                <Columns>
                                <asp:TemplateField HeaderText="">
                                 <ItemTemplate>
                                   <asp:LinkButton ID="EditButton" runat="server" CssClass="EditButton" CommandName="Edit" Text="Edit" />
                                 </ItemTemplate>
                                 </asp:TemplateField>
                                 <asp:TemplateField HeaderText="">
                                 <ItemTemplate>
                                   <asp:LinkButton ID="DeleteButton" runat="server" CssClass="DeleteButton" CommandName="DeletePart" CommandArgument='<%# Container.DataItemIndex %>' Text="Delete" />
                                 </ItemTemplate>
                                 </asp:TemplateField>
                                </Columns>
                            <HeaderStyle BackColor="#FFFFCC"  BorderColor="Black" BorderStyle="Solid" 
                                BorderWidth="2px" />
                        </asp:GridView>

Class of how the gridview populated and binded:

     public int companyID = 0;
public int methodID = 0;
DataTable dt;
#region SQLConnections

string connectionString = ConfigurationManager.ConnectionStrings["SOSConnectionString"].ConnectionString;
SqlConnection conn;
#endregion

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        dt = new DataTable();
        MakeDataTable();
        EmptyDataString();
    }
    else
    {
        dt = (DataTable)ViewState["DataTable"];
    }
    ViewState["DataTable"] = dt; 

}

#region GridView

private void EmptyDataString()
{
    TemplateBuilder tmpEmptyDataTemplate = new TemplateBuilder();
    tmpEmptyDataTemplate.AppendLiteralString("No parts has been added to the model, please add a part.");
    GridView1.EmptyDataTemplate = tmpEmptyDataTemplate;
    GridView1.DataBind();
}

private void MakeDataTable()
{
    dt.Columns.Add("Item");
    dt.Columns.Add("Quantity");
    dt.Columns.Add("Price P/Quantity");
}

private void AddToDataTable()
{
    DataRow dr = dt.NewRow();
    dr["Item"] = txtPart.Text;
    dr["Quantity"] = numQuantity.Text;
    dr["Price P/Quantity"] = txtPricePQ.Text;
    dt.Rows.Add(dr);
}

private void BindGrid()
{
    GridView1.DataSource = dt;
    GridView1.DataBind();
}

protected void btnAddPart_Click(object sender, EventArgs e)
{
    AddToDataTable();
    BindGrid();
    ClearNewParts();
}
#endregion

    protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
{
    if (e.CommandName == "Edit")
    { 
        for (int i = 0; i < GridView1.Rows.Count; i++)
        {
            GridViewRow row = (GridViewRow)(((LinkButton)e.CommandSource).NamingContainer);
            txtPart.Text = row.Cells[2].Text;
            numQuantity.Text = row.Cells[3].Text;
            txtPricePQ.Text = row.Cells[4].Text;
        }
    }
    else if (e.CommandName == "DeletePart")
    {
        //int iCount = GridView1.Rows.Count;
        //for (int i = 1; i <= iCount; i++)
        //{
        //    GridView1.DeleteRow(i);
        //}
      //  int rowIndex = Convert.ToInt32(GridView1.SelectedRow);

        int index = Convert.ToInt32(e.CommandArgument);
        GridView1.DeleteRow(index);

        //int index = Convert.ToInt32(e.CommandArgument);
        //GridView1.DeleteRow(rowIndex);
    }


    GridView1.DataBind();
}

Found the solution, only needed to do a databound.... Here is the working code:

    else if (e.CommandName == "Delete")
    {     
        int index = Convert.ToInt32(e.CommandArgument);
        GridView1.DeleteRow(index);
        ((DataTable)ViewState["DataTable"]).Rows[index].Delete();
        ((DataTable)ViewState["DataTable"]).AcceptChanges();
        GridView1.DataSource = (DataTable)ViewState["Data"];
        GridView1.DataBind();
    }