Question

我正在使用C＃中的.NET Webforms，现在我正尝试在按钮单击时在gridview中添加和减去一行。我在页脚模板中有一个添加和删除按钮，我的添加按钮工作正常，但删除了最后一行，同时保留了其他可能输入的数据，这是我拥有的问题。基本上我可以删除最后一行，但是我手工填写多行数据，当我删除最后一行时它都被删除了。我想保留输入的所有数据，只需从gridview中减去最后一行索引。这是我的gridview：

<!-- ADD COURSE GRIDVIEW -->
<asp:GridView ID="Course_Gridview" runat="server" ShowFooter="True" AutoGenerateColumns="false" class="table table-striped" GridLines="None" Visible="false">
<Columns>

    <asp:BoundField DataField="RowNumberCourse" HeaderText="Course #" />

    <asp:TemplateField HeaderText="Course">
        <ItemTemplate>
            <asp:DropDownList ID="CourseList" runat="server" DataSourceID="CourseListODS" DataTextField="SubjectName"
                    DataValueField="CourseID" AppendDataBoundItems="true" CssClass="form-control course-ddl-fix">
                <asp:ListItem Value="0">---------[Select]---------</asp:ListItem>
            </asp:DropDownList>
        <asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" 
        ErrorMessage="Please select a Program Length value from the list." Display="Dynamic" ControlToValidate="CourseList" 
        InitialValue="0" Text="*" CssClass="require-fix"></asp:RequiredFieldValidator>

        </ItemTemplate>
    </asp:TemplateField>

    <asp:TemplateField HeaderText="Mark">
        <ItemTemplate>
            <asp:TextBox ID="EnterMark" runat="server" CssClass="form-control pgm-length-fix"></asp:TextBox>
            <asp:RequiredFieldValidator ID="RequiredFieldValidator7" runat="server" 
            ErrorMessage="Please enter a Mark when inserting a course." Text="*" ControlToValidate="EnterMark"
            Display="Dynamic" CssClass="require-fix"></asp:RequiredFieldValidator>

        </ItemTemplate>

        <FooterStyle HorizontalAlign="Right" />
        <FooterTemplate>
            <asp:Button ID="ButtonAdd" runat="server" Text="Add Another Course..." OnClick="ButtonAdd_Click" CssClass="listview-buttons" CausesValidation="False"/>
            <asp:LinkButton ID="ButtonSubtract" runat="server" CssClass="btn btn-default btn-sm delete-fix"
                    OnClick="ButtonSubtract_Click" CausesValidation="false">
                <i aria-hidden="true" class="glyphicon glyphicon-remove"></i> Remove...</asp:LinkButton>
        </FooterTemplate>
    </asp:TemplateField>

</Columns>

这是减去最后一行的方法：

protected void ButtonSubtract_Click(object sender, EventArgs e)
{
    if (ViewState["CurrentTableCourse"] != null)
    {
        //create new datatable, cast datatable of viewstate
        DataTable dtCurrentTable = (DataTable)ViewState["CurrentTableCourse"];
        DataRow drCurrentRow = null;

        int rowIndex = 0;

        if (dtCurrentTable.Rows.Count > 1)
        {
            for (int i = 1; i <= dtCurrentTable.Rows.Count; i++)
            {
                //extract the values
                DropDownList courseList = (DropDownList)Course_Gridview.Rows[rowIndex].Cells[1].FindControl("CourseList");
                TextBox marks = (TextBox)Course_Gridview.Rows[rowIndex].Cells[2].FindControl("EnterMark");

                drCurrentRow = dtCurrentTable.NewRow();
                drCurrentRow["RowNumberCourse"] = i;

                dtCurrentTable.Rows[i - 1]["Column1Course"] = courseList.Text;
                dtCurrentTable.Rows[i - 1]["Column2Course"] = marks.Text;

                rowIndex++;
            }

            dtCurrentTable.Rows[rowIndex - 1].Delete();

            ViewState["CurrentTableCourse"] = dtCurrentTable;

            Course_Gridview.DataSource = dtCurrentTable;
            Course_Gridview.DataBind();
        }
    }
}

除了最后删除的值之外，我如何保留输入的所有值？

Answer 1

感谢您的回复，但我得到了它。我需要添加以下方法才能相应地工作：

private void SetPreviousCourseData()
    {
        int rowIndex = 0;

        if (ViewState["CurrentTableCourse"] != null)
        {
            DataTable dt = (DataTable)ViewState["CurrentTableCourse"];
            if (dt.Rows.Count > 0)
            {
                for (int i = 0; i < dt.Rows.Count; i++)
                {
                    DropDownList courseList = (DropDownList)Course_Gridview.Rows[rowIndex].Cells[1].FindControl("CourseList");
                    TextBox marks = (TextBox)Course_Gridview.Rows[rowIndex].Cells[2].FindControl("EnterMark");

                    courseList.Text = dt.Rows[i]["Column1Course"].ToString();
                    marks.Text = dt.Rows[i]["Column2Course"].ToString();

                    rowIndex++;
                }
            }
        }
    }

如果（！Page.IsPostBack）：

，请调用此方法

private void SetInitialCourse()
    {
        //Create DataTable
        DataTable dt = new DataTable();
        DataRow dr = null;

        //Add initail values to DataTable
        dt.Columns.Add(new DataColumn("RowNumberCourse", typeof(string)));
        dt.Columns.Add(new DataColumn("Column1Course", typeof(string)));
        dt.Columns.Add(new DataColumn("Column2Course", typeof(string)));
        //dt.Columns.Add(new DataColumn("Column3", typeof(string)));

        dr = dt.NewRow();
        dr["RowNumberCourse"] = 1;
        dr["Column1Course"] = string.Empty;
        dr["Column2Course"] = string.Empty;
        //dr["Column3"] = string.Empty;

        dt.Rows.Add(dr);
        dr = dt.NewRow();

        //Store the DataTable in ViewState
        ViewState["CurrentTableCourse"] = dt;
        Course_Gridview.DataSource = dt;
        Course_Gridview.DataBind();

    }

减去gridview行时保留值？

1 个答案: