Asp Button 不起作用，也不执行后面的功能

问：

ASP 按钮不会触发，也不会执行 C# 代码，后面有代码，导致此问题的原因是什么

protected void searchhosp(object sender, EventArgs e) {
    string cityname = city.Value;
    DataBaseConnection db  = new DataBaseConnection();
    db .disconnect();

    string sql  = "select Hospital_ID , Hospital_Name From TBL_Hospitals where City like'%"+cityname+"%'";
    SqlCommand cmd  = new SqlCommand(sql , db.connect());
    hospSelect.DataSource = cmd.ExecuteReader();
    hospSelect.DataTextField = "Hospital_Name";
    hospSelect.DataValueField = "Hospital_ID";
    hospSelect.DataBind();
    hospSelect.Items.Insert(0, "--Choose Hospital--");             
}

<input type="text" class="input2"  id="city" runat="server" > 
    <select runat="server" class="chosen" name="slct"  onchange="myFunction2();"  id="hospSelect">
</select>

<asp:Button ID="Button2" OnClick="searchhosp" CssClass="btnn" runat="server" Text="Search" />