当我单击“编辑”链接按钮时，隐藏“添加”链接按钮

Question

这是我的网站表单 my form

，当我单击以编辑链接按钮时，添加链接按钮可见 edit picture

这是我的表单代码

 <asp:TemplateField  HeaderStyle-Width="50px">  
  
    <ItemTemplate>  
 <asp:LinkButton ID="link_edit" runat="server" CommandName="edit" ToolTip="edit" Text="<span class='table-icons'><i class='fas fa-edit'></i></span>" style="width:20px"></asp:LinkButton>  
  
 <asp:LinkButton ID="link_delete" runat="server" CommandName="delete" ToolTip="delete" Text="<span class='table-icons'><i class='fas fa-times'></i></span>" style="width:20px;" OnClientClick="return confirm('Are you sure you want to delete this record?');"></asp:LinkButton>  
  
  </ItemTemplate>  
  
 <EditItemTemplate>  
<asp:LinkButton ID="link_update" runat="server" CommandName="Update" ToolTip="Update" Text="<span class='table-icons'><i class='far fa-save'></i></span>" style="width:20px;"></asp:LinkButton>  
  
<asp:LinkButton ID="link_cancel" runat="server" CommandName="Cancel" ToolTip="cancel" Text="<span class='table-icons'><i class='fas fa-times'></i></span>" style="width:20px;"></asp:LinkButton>  
                                                                              
</EditItemTemplate>  
  
                                                                              
<HeaderTemplate>  
                                               
 <label style="color: #3366FF">Action</label>                                                                                  
<asp:LinkButton ID="link_add" runat="server" ValidationGroup="company_country" CausesValidation="true" CommandName="addnew" ToolTip="addnew" Text="<span class='table-icons' style='font-size:15pt;'><i class='far fa-save'></i></span>"></asp:LinkButton>  
                                                                             
 </HeaderTemplate>  
                                                                         
 </asp:TemplateField>  

这是我要定义的函数invisible = false

protected void GridView_cause_RowEditing(object sender, GridViewEditEventArgs e)  
        {  
            GridView_cause.EditIndex = e.NewEditIndex;  
            PARAM_CAUSE_DEPARTURE_DAO cause = new PARAM_CAUSE_DEPARTURE_DAO(this._sSqlConnectionString);  
            display_cause();  
            cause.edit(GridView_cause);  
            display_cause_form();  
        }  

请帮助我