Textbox asp.net postback trigger twice on autopostback true

问题

On textbox OnTextChanged event the postback cycle triggering twice. Breakpoints on both methods to understand the issue. Here is my code sample

<form id="form1" runat="server">
    <div>
        <asp:TextBox runat="server" ID="TextBox1" OnTextChanged="TextBox1_TextChanged" AutoPostBack="true" />
    </div>
    <asp:Label ID="Label1" runat="server"></asp:Label>
</form>

Its code behind.

     public static int cycle { get; set; }
     protected void Page_Load(object sender, EventArgs e)
     {

     }
     protected void TextBox1_TextChanged(object sender, EventArgs e)
     {
        cycle++;
        Label1.Text = cycle.ToString(); 
     }

回答1:

Avoid using AUTOPOSTBACK, keep the OnTextChanged event trap and add a button (hidden or not) to catch the return pression on the textbox to produce the POSTBACK.

Here is an example

        <asp:Panel runat="server" CssClass="col-md-2">
            <asp:Panel runat="server" CssClass="form-group input-group" DefaultButton="BTN_Cerca">
                <span class="input-group-btn">
                    <asp:Button runat="server" ID="BTN_Cerca" Text="Codice" CssClass="btn btn-secondary" ToolTip="Cerca in magazzino"/>
                </span>
                <asp:TextBox runat="server" ID="TXT_Search" CssClass="form-control" placeholder="Numero Articolo" OnTextChanged="TXT_Search_TextChanged" />
            </asp:Panel>
        </asp:Panel>

来源：https://stackoverflow.com/questions/40673957/textbox-asp-net-postback-trigger-twice-on-autopostback-true