为什么ListBox1.SelectedIndex的值等于-1protected void btnDeleteType_Click(object sender, EventArgs e) { if (this.lstCardType.SelectedIndex != -1) { string typeId = this.lstCardType.SelectedItem.Value; bool

来源：学生作业帮助网 编辑：作业帮 时间：2024/04/28 21:29:44

为什么ListBox1.SelectedIndex的值等于-1

protected void btnDeleteType_Click(object sender, EventArgs e)

    {

        if (this.lstCardType.SelectedIndex != -1)

        {

            string typeId = this.lstCardType.SelectedItem.Value;

            bool deleteCardtype = CardManager.DeleteCardTypeByCardTypeId(typeId);

            if (deleteCardtype)

            {

                DispalyCardPrice();

            }

        }

        else

        {

            Page.ClientScript.RegisterStartupScript(this.GetType(), "OK", "<script>alert('删除失败!');</script>");

        }

    }

怎么只能输入1000个字符,我一个处理方法都不止1000个字符了

小溪默默地等待着
并且歌颂
——犯更多的错误,
是繁星点点
微风中,昨天在动摇并吱吱作响.
孤坟一座何处话凄凉.哈哈

C# 中 listBox1.SelectedIndex!= 为什么ListBox1.SelectedIndex的值等于-1protected void btnDeleteType_Click(object sender, EventArgs e) { if (this.lstCardType.SelectedIndex != -1) { string typeId = this.lstCardType.SelectedItem.Value; bool listbox1.items(listbox1.selectedindex) 和 listbox1.items.add(listbox1.selectedindex) 加ADD和不加ADD的区别 烦请解释一下这句话的意思 this.listBox1.Items.Clear();这句话是什么意思? Stitch Selected selected 意思 They selected Tom,____ they liked ,as captain .为什么要用whom printer selected is not selected countries是什么意思 selected什么意思 randomly selected是什么意思 No items were selected! No map selected是什么意思 kill selected apps wrong file selected是什么意思 scientifically selected employees是什么意思 No objects selected是什么意思 No files selected.