Question

在我的ASP.Net的webform上，我从SQL Server显示一个表。但是，我想要做的是为网页用户提供检查某些框的功能，并在刷新页面后仅显示这些特定的列。

这是aspx html：

<div style="width: 1250px; height: 300px; overflow: auto">
    <asp:GridView ID="GridView1" HeaderStyle-BackColor="Black" HeaderStyle-ForeColor="Silver" RowStyle-BackColor="#EEEEEE" AlternatingRowStyle-BackColor="White" 
        AlternatingRowStyle-ForeColor="#000" runat="server" AutoGenerateColumns ="false" AllowPaging="false" OnPageIndexChanging="OnPageIndexChanging" AllowSorting="True">
        <Columns>
            <asp:BoundField DataField ="WeekEndingDate" HeaderText="Week Ending Date" ItemStyle-Width="150px" dataformatstring="{0:MM-dd-yyyy}" />
            <asp:BoundField DataField ="Week_Number" HeaderText="Week Number" ItemStyle-Width="150px" />
            <asp:BoundField DataField ="Class" HeaderText="Class" ItemStyle-Width="150px" />
            <asp:BoundField DataField ="Animal" HeaderText="Animal" ItemStyle-Width="150px" />
            <asp:BoundField DataField ="North_Island" HeaderText="North Island" ItemStyle-Width="150px" DataFormatString="{0:F2}" />
            <asp:BoundField DataField ="South_Island" HeaderText="South Island" ItemStyle-Width="150px" DataFormatString="{0:F2}" />
            <asp:BoundField DataField ="New_Zealand" HeaderText="New Zealand" ItemStyle-Width="150px" DataFormatString="{0:F2}" />
        </Columns>
    </asp:GridView>
</div>

这是bindgrid方法：

private void BindGrid()
    {
        string strConnString = "server= N-1077; Trusted_Connection=yes; database=Slaughter; connection timeout=30";
        using (SqlConnection con = new SqlConnection(strConnString))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT CONVERT(date, Week_Ending_Date) AS WeekEndingDate," + 
                "Week_Number, Class, North_Island = CAST(North_Island as float), South_Island = CAST(South_Island as float)," +
                "(CAST(North_Island as float)) + (CAST(South_Island as float)) AS New_Zealand," +
                "Animal = (CASE WHEN Class = 'Sheep' OR Class = 'Lamb' THEN 'Ovine' WHEN Class = 'Calf' THEN 'Calf' ELSE 'Bovine' END)" +
                "FROM Slaughter ORDER BY WeekEndingDate DESC"))
            {
                using (SqlDataAdapter sda = new SqlDataAdapter())
                {
                    cmd.Connection = con;
                    sda.SelectCommand = cmd;
                    using (DataTable dt = new DataTable())
                    {
                        sda.Fill(dt);
                        GridView1.DataSource = dt;
                        GridView1.DataBind();
                    }
                }
            }
        }
    }

是否有一种简单的方法可以选择特定列并仅显示这些列？即如果他们只对weeknumber，class和south_island感兴趣，它只显示这三列的数据？我不介意根据用户输入构建SQL查询，但我是如何更改boundfield数据字段以反映在该查询中选择的那些列。

Answer 1

这是使用Visible属性执行此操作的一种方法。

protected void RefreshSQLDisplay(object sender, EventArgs e)
{
    foreach (BoundField col in GridView1.Columns)
    {
        if (col.DataField == "WeekEndingDate")
        {
            col.Visible = false;
            break;
        }
    }
}

缺点是列仍将在内存中，而sql查询将检索数据。因此，出于性能原因，最好更改sql查询。

更新：我按照您的要求编辑了代码

从SQL select语句显示动态网格视图

1 个答案: