删除gridview的单个行，而不从数据库中删除

Question

I am using Linq-to-SQL in ASP.NET & C#. I want to delete individual row of gridview by click on delete button (ie CommandField or TemplateField ) with gridTrainingNeed_RowDeleting event.

Here is my code for loading gridview on page load.

int departmentId;
int branchId;
int positionId;
double month;
int levelId;

protected void Page_Load(object sender, EventArgs e)
{
        if (!IsPostBack)
        {
            Initialize();
        }
}

public void Initialize()
{
        ddlBranch.DataSource = TrainingManager.GetBranchName();
        ddlBranch.DataBind();

        ddlDepartment.DataSource = DepartmentManager.GetAllDepartments();
        ddlDepartment.DataBind();

        ddlPosition.DataSource = TrainingManager.GetDesignationName();
        ddlPosition.DataBind();

        ddlLevel.DataSource = TrainingManager.GetLevelName();
        ddlLevel.DataBind();

        gridTrainingNeed.DataSource = TrainingManager.GetAllEmployees(departmentId, branchId, positionId, month, levelId).ToList();
        gridTrainingNeed.DataBind();
}

Now I am going to keep my design code:

 <div class="innerLR">
<div class="seperator bottom" />
    <div class="widget">
<div class="widget-head">
<h4 class="heading">
Send Circulation To
</h4>
</div>
<div class="widget-body">
    <table class="tableShow" cellpadding="3" cellspacing="0">
        <tr>
            <td>
                <asp:DropDownList ID="ddlBranch" runat="server" DataTextField="Name" 
                    DataValueField="BranchId" Width="170px" AppendDataBoundItems="True" 
                    >
                    <asp:ListItem Text="---Select Branch---"/>
                </asp:DropDownList>
               </td>
            <td>
                <asp:DropDownList ID="ddlDepartment" runat="server" AppendDataBoundItems="True" 
                    DataTextField="Name" Width="170px" DataValueField="DepartmentId">
                    <asp:ListItem Text="---Select Department---"/>
                </asp:DropDownList></td>
            <td>
                <asp:DropDownList ID="ddlLevel" runat="server" DataTextField="Name" 
                    DataValueField="LevelId" Width="170px" AppendDataBoundItems="True" 
                    >
                    <asp:ListItem Text="---Select Level---"/>
                </asp:DropDownList></td>
            <td>
                <asp:DropDownList ID="ddlPosition" runat="server" DataTextField="Name" 
                    DataValueField="DesignationId" Width="170px" AppendDataBoundItems="True" 
                    >
                    <asp:ListItem Text="---Select Position---"/>
                </asp:DropDownList></td>
        </tr>
        <tr>
            <td>

                <br />

                Send Circulation To</td>
            <td>
                <br />
                Month</td>
            <td>
                &nbsp;</td>
            <td>
                &nbsp;</td>
        </tr>
        <tr>
            <td>
                <asp:DropDownList ID="ddlCirculation" runat="server" DataTextField="Name" 
                    DataValueField="PositionId" Width="170px" AutoPostBack="true" AppendDataBoundItems="True" 
                    onselectedindexchanged="ddlCirculation_SelectedIndexChanged">
                <asp:ListItem Text="" Value="-1" />
                <asp:ListItem Text="All" Value="0" />
                <asp:ListItem Text="Must Have Worked For" Value="1" />
                </asp:DropDownList></td>
            <td>
                <asp:TextBox ID="txtMonth" Width="150px" runat="server" Enabled="false"></asp:TextBox></td>
            <td>
                <asp:Button ID="btnShow" runat="server" Text="Show" onclick="btnShow_Click" /></td>
            <td>
                &nbsp;</td>
        </tr>
    </table>
    </div>
    </div>




<div>
    <asp:GridView ID="gridTrainingNeed" runat="server" AutoGenerateColumns="False" 
        EnableModelValidation="True" CellPadding="4" ForeColor="#333333" 
        GridLines="None" >
        <AlternatingRowStyle BackColor="White" ForeColor="#284775" />
        <Columns>
            <asp:BoundField DataField="EmployeeId" HeaderText="EID" />
            <asp:BoundField DataField="Name" HeaderText="Name" />
            <asp:BoundField DataField="Branch" HeaderText="Branch" />
            <asp:BoundField DataField="Department" HeaderText="Department" />
            <asp:BoundField DataField="Level" HeaderText="Level" />
            <asp:BoundField DataField="Position" HeaderText="Position" />
            <asp:CommandField HeaderText="Delete" ShowCancelButton="False" 
                ShowDeleteButton="True" />
        </Columns>
        <EditRowStyle BackColor="#999999" />
        <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
        <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
        <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
        <RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
        <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
    </asp:GridView>

</div>
</div>

Thus, I want to delete row one by one with RowDeleting Event from displaying data on gridview not from database.

 protected void gridTrainingNeed_RowDeleting(object sender, GridViewDeleteEventArgs e)
  {//Row delete code
   }

Thank You.

Answer 1

Instead of assigning the DataSource directly like you are doing:

gridTrainingNeed.DataSource = TrainingManager.GetAllEmployees(departmentId, branchId, positionId, month, levelId).ToList();

Store the result in Page level List. Define a page level List like:

//Define List at page/class level
List<Employee> gridList = new List<Employee>();

Then in your method Initialize

gridList = TrainingManager.GetAllEmployees(departmentId, branchId, positionId, month, levelId).ToList();
gridTrainingNeed.DataSource = gridList;
gridTrainingNeed.DataBind();

You need to persist the List<Employee> in memory on PostBack, Use Session/ViewState etc. (See ASP.Net State Management ).

Later in your gridTrainingNeed_RowDeleting , get the ID from row or any field that uniquely identify an employee. Query your list and remove that object from the List in memory. Re-assign the DataSource to the modified list and call DataBind.