如果文本发生更改，如何比较和检查带有标签值的文本框值？

Question

我有一个文本框和标签，彼此相邻。 标签的文本值来自一个下拉列表。 如果label的值小于text box的值并且一直持续到在textbox中输入正确的值，则必须将文本框的焦点转到自身。 你能帮助我吗？

这是我的代码：-.aspx文件：-

<div class="row mb10">
   <asp:Label runat="server" ID="lbl_Adults" CssClass="col-lg-2 control-label" Text="Adults : " AssociatedControlID="txt_Adults"></asp:Label>
      <div class="col-lg-6">
          <div class="col-lg-4" style="margin-left:-15px;">
              <asp:TextBox runat="server" ID="txt_Adults" CssClass="form-control" OnTextChanged="txt_Adults_TextChanged" AutoPostBack="true"></asp:TextBox>
              <asp:RequiredFieldValidator Font-Bold="true" ForeColor="Red" runat="server" ID="req_Adults" ControlToValidate="txt_Adults" ErrorMessage="Enter No. of Adults"></asp:RequiredFieldValidator>
          </div>
          <div class="col-lg-8" style="font-family:'Copperplate Gothic'">
                Only <asp:Label runat="server" ID="lbl_No_Of_Adults"></asp:Label> Adult(s) allowed.
          </div>
    </div>
</div>

这是.cs文件代码：-

protected void txt_Adults_TextChanged(object sender, EventArgs e)
  {

     while (true)
     {
         if (txt_Adults==null)
         {
             txt_Adults.Text = Convert.ToString("0");
             txt_Adults.Focus();
             //txt_Adults_TextChanged(sender, e);
         }
         else if (Convert.ToInt32(txt_Adults.Text) > Max_NoAdults)
         {
             txt_Adults.Text = Convert.ToString("0");
             txt_Adults.Focus();
             //txt_Adults_TextChanged(sender, e);

         }
         else
         {
             NoAdults = Convert.ToInt32(txt_Adults.Text);
             //NoAdults is a static variable that collects final(right) value of txt_Adults.text;
             break;
         }

     }

 }

Answer 1

只需这样做

protected void txt_Adults_TextChanged(object sender, EventArgs e)
{
   //this condition will always be true unless and until both the `Text`
   //string are same
   if (lbl_No_Of_Adults.Text.Trim() != txt_Adults.Text.Trim())
   {
      txt_Adults.Focus(); 
   }
}

否则，仅当Label值小于TextBox要匹配条件。

protected void txt_Adults_TextChanged(object sender, EventArgs e)
{
   int a = 0 , b =0;
   int.TryParse(lbl_No_Of_Adults.Text.Trim(), out  a);
   int.TryParse(txt_Adults.Text.Trim(), out  b);

   if (a < b)
   {
      txt_Adults.Focus(); 
   }
}