Question

我创建了一个数据表globaly，我在页面加载事件中添加了列。现在我想在按钮点击事件中添加数据。当我这样做时，我得到一个错误说....

列'catID'不属于表

解决方案是什么......我需要使用会话......？代码如下所示

    public partial class Default2 : System.Web.UI.Page
{
    DataTable dtSelectedSeats = new DataTable();

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            dtSelectedSeats.Columns.Add("catID", typeof(string));
            dtSelectedSeats.Columns.Add("seatID", typeof(string));
        }

    }
    protected void seat_Click(object sender, EventArgs e)
    {
        Button button = (Button)sender;

        if (button.BackColor == Color.Cyan)
        {
            button.BackColor = Color.Lime;

            addSeat(button.Text);
        }

    }

    private void addSeat(string seatNo)
    {
        DataRow dr;
        dr = dtSelectedSeats.NewRow();
        dr["catID"] = ddlCategory.SelectedItem.Value.ToString();
        dr["seatID"] = seatNo;
        dtSelectedSeats.Rows.Add(dr);
    }
}

Answer 1

ASPX：

<asp:DropDownList ID="ddlCategory" runat="server">
<asp:ListItem>a</asp:ListItem>
<asp:ListItem>b</asp:ListItem>
<asp:ListItem>c</asp:ListItem>
</asp:DropDownList>
<asp:Button ID="seat" runat="server" BackColor="Cyan" onclick="seat_Click" Text="1" />
<asp:Button ID="Button1" runat="server" BackColor="Cyan" onclick="Button1_Click" Text="2" />
<asp:Button ID="Button2" runat="server" BackColor="Cyan" onclick="Button2_Click" Text="3" /><br />
<asp:GridView ID="GridView1" runat="server"/>

代码背后：

protected void seat_Click(object sender, EventArgs e)
{
    Button button = (Button)sender;
    if (button.BackColor == Color.Cyan)
    {
        button.BackColor = Color.Lime;
        addSeat(button.Text);
    }
}
private void addSeat(string seatNo)
{
    if (Session["dt"] == null)
    {
        Response.Write("DataTable not exist!");
        return;
    }
    DataTable dtSelectedSeats = (DataTable)Session["dt"];
    DataRow dr = dtSelectedSeats.NewRow();
    dr["catID"] = ddlCategory.SelectedItem.Value.ToString();
    dr["seatID"] = seatNo;
    dtSelectedSeats.Rows.Add(dr);
    GridView1.DataSource = dtSelectedSeats;
    GridView1.DataBind();
    Session["dt"] = dtSelectedSeats;
}
protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        DataTable dtSelectedSeats = new DataTable();
        dtSelectedSeats.Columns.Add("catID", typeof(string));
        dtSelectedSeats.Columns.Add("seatID", typeof(string));
        Session["dt"] = dtSelectedSeats;
    }
}
protected void Button1_Click(object sender, EventArgs e)
{
    seat_Click(sender, e);
}
protected void Button2_Click(object sender, EventArgs e)
{
    seat_Click(sender, e);
}

Answer 2

删除if (!IsPostBack) 当你点击按钮时，页面会回发。

Answer 3

您的代码对DataTable完全正确，您获得的错误可能是针对某些不同的问题。请正确指出您的错误

Answer 4

就在我的脑海中，看起来好像是在错误的事件中添加行。我不确定您的DataTable是否已在向其添加列时初始化（因此丢弃了您的更改）。尝试将您的PageLoad代码放入PagePrerender，看看是否能给您带来更好的结果。

如何将行添加到数据表中

4 个答案: