Syncfusion HTMLUI研究一

HTMLUI可以加载HTML页面，并且相比WebKit等占用资源特别少

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html>

<body marginheight="0" marginwidth="0" bgcolor="#ffffff">

<div>

    <span style="font:Bold">12121</span>

    <span style="font:Bold;Color:Blue">121212</span>

    <span style="font:Bold;Color:Blue">121212</span>

</div>

<hr></hr>

<div>

    <span style="font:Bold;font-size:9pt">1212</span>

    <span style="font:Bold;font-size:9pt">1221</span>

    <span style="font:Bold;font-size:9pt">1212</span>

</div>

<p>

    <span style="font:Bold;font-size:9pt">12121</span>

    <span id="aaa" style="width:24px;height:24px;"></span>

    <span style="font:Bold;font-size:9pt">121212</span>

</p>

</div>

</body>

</html>

Syncfusion HTMLUI研究一-LMLPHP

（1）HTMLUI源码中绘制部分

/// <summary>

/// Starts the drawing of the document from the start element.

/// </summary>

/// <param name="e">Paint event data.</param>

private void ProcessDraw(PaintEventArgs e)

{

    if (e == null)

        throw new ArgumentNullException("e");

    if (m_startDrawElement == null)

    {

        this.RenderRoot.DrawElement(e);

    }

    else

    {

        m_startDrawElement.DrawElement(e);

        // Reset start element.

        m_startDrawElement = null;

    }

}

如果m_startDrawElement为null，在根html tag下绘制，否则在指定元素下绘制。
（2）FlowLayoutPanel中使用HTMLUI时，要先用一个UserControl或者其它控件作为HTMLUI的父控件，不然滚动时会出现花屏现象。

（3）动态改变HTMLUI元素内容代码

private void htmluiControl1_PreRenderDocument(object sender, Syncfusion.Windows.Forms.HTMLUI.PreRenderDocumentArgs e)

        {

            Hashtable htmlelements = new Hashtable();

            htmlelements = e.Document.ElementsByUserID;

            Label lable=new Label();

            lable.Text = "";

            lable.Width = ;

            lable.Height = ;

            lable.BackColor = Color.Red;

            BaseElement aaa = htmlelements["aaa"] as BaseElement;

                new CustomControlBase(aaa, lable);

        }

        private void ChangeLableValue(HTMLUIControl htmluiControl,string str)

        {

            var v = htmluiControl.Document.GetElementsByUserIdHash()["aaa"];

            Label v1= htmluiControl.Document.GetControlByElement((IHTMLElement) v) as Label;

            v1.Text = str;

        }

（4）有时创建会报线程间操作无效: 从不是创建控件“”的线程访问它，经检查原因在PreRenderDocument,修改PreRenderDocument如下。

private void htmluiControl1_PreRenderDocument(object sender, Syncfusion.Windows.Forms.HTMLUI.PreRenderDocumentArgs e)

        {

            Hashtable htmlelements = new Hashtable();

            htmlelements = e.Document.ElementsByUserID;

            Action<Hashtable> action = (data) =>

            {

                Label lable = new Label();

                lable.Text = "";

                lable.Width = ;

                lable.Height = ;

                lable.BackColor = Color.Red;

                BaseElement aaa = htmlelements["aaa"] as BaseElement;

                new CustomControlBase(aaa, lable);

            };

            Invoke(action, htmlelements);

        }

一起研究的来群：616945527