自定义控件事件无法正常触发

[local]1[/local]这是自定义控件中的代码

 public virtual void btn_Click(object sender, EventArgs e)
        {
            EventArgs arg = new EventArgs();
            if (LoginClick != null)
            {
                LoginClick(btn, arg);
            }
        }
        protected override void CreateChildControls()
        {
            lbl.ID = "lblWord";
            btn.ID = "btnWord";
            txt.ID = "txtWord";
            txt.AutoPostBack = true;
            btn.Click += new EventHandler(btn_Click);
            this.Controls.Add(lbl);
            this.Controls.Add(txt);
            this.Controls.Add(btn);
           // base.CreateChildControls();
        }
        protected override void Render(HtmlTextWriter writer)
        {
            writer.Write("<div>");
            lbl.RenderControl(writer);
            txt.RenderControl(writer);
            btn.RenderControl(writer);
            writer.Write("</div>");
        }

这是3个核心的方法，下面是客户端中的事件，此事件已经正确绑定
    protected void ServerControl1_LoginClick(object sender, EventArgs e)
    {
        Label1.Text =(ServerControl1.FindControl("txtWord") as TextBox).Text;
    }
页面运行是这样的，首先页面加载正常，然后在文本框中输入一个值通过触发ServerControl1_LoginClick发放在一个临时lable中显示该值
但是点击按钮的时候 按钮点击2此才能显示，请高手解答