Question

我为下拉列表选择值编写代码添加列表框和文本字段，我可以删除列表框值但不能删除文本字段值，请如何编写代码删除文本字段的相同添加值和列表框

我添加下拉列表值AA，其显示列表框和文本框，但单击删除按钮始终删除所选列表框项但不删除文本框值

<div class="col-sm-3">
                                            <asp:TextBox ID="txtQlt" runat="server" CssClass="form-control" Width="348px" OnTextChanged="txtQlt_TextChanged" ReadOnly="true"></asp:TextBox>


                                        </div><div class="col-md-1" style="margin-left:115px;">
                    <asp:Label ID="Label4" runat="server" ForeColor="Red" Text="*" ></asp:Label>
                        </div>   
                                    </div>

                                    <br />
                                       <div class="row">
                                        <div class="col-sm-2">

                                            <asp:Label ID="Label6" runat="server" Text="Quality reference"  Font-Bold="True" Font-Names="arial, helvetica, sans-serif" Font-Size="13px"></asp:Label>
                                        </div>
                                        <div class="col-sm-3">
                                        <asp:DropDownList ID ="cmbQualityRef" runat ="server" CssClass="form-control" Width="250px" >

                                        </asp:DropDownList>
                                        <asp:ListBox  ID="lstValue" runat="server" CssClass="content" Rows="5" ValidationGroup="save"
                                            Width="250"  ></asp:ListBox>

                                        </div>
                                    <asp:ImageButton  ID="btnAdd" runat="server" CssClass="button" Text="Add" ValidationGroup="add"
                                            OnClick="btnAdd_Click"  ImageUrl="~/img/Add.png"/>

                                           <asp:ImageButton   ID="btnImageRemove" runat="server" OnClick="btnImageRemove_Click"
                                                         ImageUrl="~/img/Remove.png" /> 

                                            <div class="col-md-1" style="margin-left:16px;">
                    <asp:Label ID="Label7" runat="server" ForeColor="Red" Text="*" ></asp:Label>
                        </div>   
                                    </div>

     protected void btnAdd_Click(object sender, EventArgs e)
            {

                AddToList();






                        lstValue.Items.Remove("");


            }
--------------------------------------------
private void AddToList()
        {

            if (lstValue.Items.FindByText(cmbQualityRef.SelectedItem.ToString()) == null)
            {
                if (lstValue.Items.Count > 0)
                {
                    txtQlt.Text = txtQlt.Text + "," + cmbQualityRef.SelectedItem.ToString();
                }
                else
                {
                    txtQlt.Text = cmbQualityRef.SelectedItem.ToString();
                }
                ListItem itm = new ListItem();
                itm.Value = cmbQualityRef.SelectedValue;
                itm.Text = cmbQualityRef.SelectedItem.ToString();
                lblMsg.Text = "";

                lstValue.Items.Add(itm);
            }
            else
            {
                lblMsg.Text = "Selected Item Already Exists In The List.";
                lblMsg.ForeColor = System.Drawing.Color.Red;

            }

        }

 protected void btnImageRemove_Click(object sender, ImageClickEventArgs e)
        {
            try
            {



                if (lstValue.SelectedItem != null)
                {


                    lstValue.Items.Remove(lstValue.SelectedItem);
                    txtQlt.Text = txtQlt.Text.Replace(lstValue.SelectedItem.ToString(), "").Trim();

               }






            }


            catch (Exception)
            {


          }
       }

Answer 1

您应该在替换字符串后从列表中删除项目，否则它无法从列表中找到该项目。您的代码如下：

 protected void btnRemove_Click(object sender, EventArgs e)
{
    try
    {
        if (lst.SelectedItem != null)
        {
            txt.Text = txt.Text.Replace(lst.SelectedItem.ToString(), "").Trim();
            lst.Items.Remove(lst.SelectedItem);
        }
    }
    catch (Exception)
    {

    }
}

列表框添加项目已删除但文本框项目未删除

1 个答案: