选中添加为模板字段的复选框时，如何从gridview控件中的一行中检索对应的数据

Question

I am a beginner in ASP.NET and I am not a code genius. I am hoping someone can help.

So I created a web form and added a gridview control to it. The gridview contains Two columns: Name_EN(the name of the subject), Select Subjects(a template column that contains a checkbox).

Ultimately I want a student to use this web form to register his subjects. So whenever he clicks a submit button, he will be registered in all the subjects that he has selected using the checkbox.

I thought I could test this with adding a button that will print -on the web form- the Names of the subjects that I select.

This is the HTML and CSS code for the GridView.

<asp:GridView ID="dgvUsers" runat="server" 
    CssClass="table table-hover table-striped" GridLines="None" 
    AutoGenerateColumns="False" DataSourceID="source1" >
    <Columns>
        <asp:BoundField DataField="Name_EN" HeaderText="Name_EN" SortExpression="Name_EN" />
        <asp:TemplateField HeaderText="Select Subjects">
            <ItemTemplate>
                <asp:CheckBox ID="CheckBox1" runat="server" Text='<%# Eval("Name_EN", "{0}") %>' />
            </ItemTemplate>
        </asp:TemplateField>  
    </Columns>
    <SelectedRowStyle BackColor="#CC3333" Font-Bold="True" ForeColor="White" />
    <RowStyle CssClass="cursor-pointer" />
</asp:GridView>

<asp:SqlDataSource ID="source1" runat="server" ConnectionString="<%$ ConnectionStrings:BIS1ConnectionString %>" SelectCommand="spViewAvailableSubjects" SelectCommandType="StoredProcedure">
    <SelectParameters>
        <asp:SessionParameter Name="ID" SessionField="ID" Type="Int32" />
    </SelectParameters>
</asp:SqlDataSource>

Then I need to view all the selected data from the "Name_EN" column but only for the rows where I checked the checkboxes when I click this Button:

<asp:Button ID="ViewButton" runat="server" CssClass="btn btn-primary" Text="View Selected Subjects" OnClick="ViewButton_Click"/>

I am thinking to print the data using the Response.Write(); method.

But I am still a beginner with ASP.NET and I don't know how to implement that in code or how to connect the checkboxes with their corresponding data in the row.

I just want to retrieve the data and print them.

Can anyone help me with that?

 <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Registration Page.aspx.cs" Inherits="IntegratedSystems.Registration_Page" MasterPageFile="Site1.Master" %> <asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" runat="server"> <div class="container-fluid"> <div class="container-fluid"> <%-- <form draggable="true" runat="server" style="max-width: 230px; text-align: left;">--%> <ul style="max-width: 230px; text-align: left;" class="nav nav-pills nav-stacked"> <li class="text-left"> <asp:Hyperlink ID="HomeLink" runat="server" CssClass="btn " NavigateUrl="~/Student's Portal.aspx">Home</asp:Hyperlink> </li> <li class="text-left"> <asp:HyperLink ID="InstructorLink" runat="server" CssClass="btn ">Choose Instructors</asp:HyperLink> </li> <li class="text-left"> <asp:HyperLink ID="TimeLink" runat="server" CssClass="btn ">Choose Time</asp:HyperLink> </li> <li class="text-left"> <asp:LinkButton ID="LinkButton1" runat="server" OnClick="HomeBtn_Click" CssClass="btn ">Logout</asp:LinkButton> </li> </ul> <br/> <label class="label label-info">These are the Available Subjects for your Registration</label> <asp:GridView ID="dgvUsers" runat="server" CssClass="table table-hover table-striped" GridLines="None" AutoGenerateColumns="False" DataSourceID="source1"> <Columns> <asp:BoundField DataField="Name_EN" HeaderText="Name_EN" SortExpression="Name_EN" /> <asp:TemplateField HeaderText="Select Subjects"> <ItemTemplate> <asp:CheckBox ID="CheckBox1" runat="server" Text='<%# Eval("Name_EN", "{0}") %>' /> </ItemTemplate> </asp:TemplateField> </Columns> <SelectedRowStyle BackColor="#CC3333" Font-Bold="True" ForeColor="White" /> <RowStyle CssClass="cursor-pointer" /> </asp:GridView> <asp:GridView ID="GridView1" CssClass="table table-hover table-striped" GridLines="None" runat="server"> </asp:GridView> <asp:SqlDataSource ID="source1" runat="server" ConnectionString="<%$ ConnectionStrings:BIS1ConnectionString %>" SelectCommand="spViewAvailableSubjects" SelectCommandType="StoredProcedure"> <SelectParameters> <asp:SessionParameter Name="ID" SessionField="ID" Type="Int32" /> </SelectParameters> </asp:SqlDataSource> <br/> <asp:Button ID="ViewButton" runat="server" CssClass="btn btn-primary" Text="View Selected Subjects" OnClick="ViewButton_Click" /> <%--</form>--%> </div> </div> </asp:Content> 

And here is the code behind file for the ViewButton click event:

protected void ViewButton_Click(object sender, EventArgs e)
    {

        List<string> selectedSubjects = new List<string>();
        foreach (GridViewRow gvr in dgvUsers.Rows)
        {
            CheckBox chk = (CheckBox) gvr.Cells[1].FindControl("CheckBox1");
            if (chk.Checked)
            {
                selectedSubjects.Add(chk.Text);

            }
        }

        if (selectedSubjects.Count > 0)
        {
            GridView1.DataSource = selectedSubjects;
            GridView1.DataBind();
        }
    }

Answer 1

To iterate through your gridview:

protected void ViewButton_Click(object sender, EventArgs e) {
    List<string> selectedSubjects = new List <string> ();
    foreach(GridViewRow gvr in dgvUsers.Rows) {
        CheckBox chk = (CheckBox) gvr.Cells[1].FindControl("CheckBox1");
        if (chk.Checked) {
            selectedSubjects.Add(chk.Text);
        }
    }

    if (selectedSubjects.Count > 0) {
        gvSelected.DataSource = selectedSubjects;
        gvSelected.DataBind();
    }
}

To display message to the user, add another gridview to the form:

<asp:GridView ID="gvSelected" runat="server">
</asp:GridView>

Obviously, pretty it up as much as you can.

I personally, would not advise using Response.Write in web forms; the whole point of them is to bind controls to code behind, not imitate classic asp.