Answer 1

Answer 2

Answer 3

这是适合你的东西。在您的代码隐藏中：

// Workaround for PayPal form problem
CustomForm mainForm = new CustomForm();
mainForm.RenderFormTag = false;

创建一个覆盖HtmlForm类的自定义表单类：

public class CustomForm : System.Web.UI.HtmlControls.HtmlForm
{
    protected bool _render;

    public bool RenderFormTag
    {
        get { return _render; }
        set { _render = value; }
    }

    public CustomForm()
    {
        //By default, show the form tag
        _render = true;
    }

    protected override void RenderBeginTag(HtmlTextWriter writer)
    {
        //Only render the tag when _render is set to true
        if (_render)
            base.RenderBeginTag(writer);
    }

    protected override void RenderEndTag(HtmlTextWriter writer)
    {
        //Only render the tag when _render is set to true
        if (_render)
            base.RenderEndTag(writer);
    }
}