列表框添加項目刪除但文本框項目不刪除

Question

我寫下拉列表選擇值的代碼添加列表框和文本字段，我可以刪除列表框值，但不能刪除文本字段值，請如何寫代碼刪除相同的文本字段和列表框的添加值

添加下拉列表值AA，其顯示列表框和文本框，但單擊刪除按鈕總是刪除選定的列表框項目但不刪除文本框值

<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

您應該更換後的字符串從列表中刪除項，其他明智它無法找到列表中的項目。 您的代碼看起來像：

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) 
    { 

    } 
}