How to get HTML of HtmlControl object in backend - c#

I have a short snippet of C# code like this:
HtmlGenericControl titleH3 = new HtmlGenericControl("h3");
titleH3.Attributes.Add("class", "accordion");
HtmlAnchor titleAnchor = new HtmlAnchor();
titleAnchor.HRef = "#";
titleAnchor.InnerText = "Foo Bar";
titleH3.Controls.Add(titleAnchor);
What I want is a way to return a string that looks like this:
<h3 class="accordion">Foo Bar</h3>
Any thoughts or suggestions?

This is the method that I have used in the past to get a control's rendered HTML ahead of time (make sure to include System.IO):
protected string ControlToHtml(Control c)
{
StringWriter sw = new StringWriter();
HtmlTextWriter htmlWriter = new HtmlTextWriter(sw);
c.RenderControl(htmlWriter);
return sw.ToString();
}
Returns this for your test case:
<h3 class="accordion">Foo Bar</h3>

Here is an example that you can use to extend any HtmlControl to have a Render() method:
public static string Render(this HtmlAnchor TheAnchor)
{
StringWriter sw = new StringWriter();
HtmlTextWriter htmlWriter = new HtmlTextWriter(sw);
TheAnchor.RenderControl(htmlWriter);
return sw.ToString();
}

Shouldn't there be a Render method that forces it to emit its own HTML?

Related

Insert Link Button In String Builder

I created a dynamic link button, which needs to be inserted in a StringBuilder to not ruin the design of my aspx page.
So here's a "part" of my code where I need to insert my LinkButton:
design.Append("<h3>");
NewAddToCart(); //This is where my linkbutton should be inserted
design.Append("</h3></div>");
My NewAddToCart() is constructed on the following code:
private void NewAddToCart()
{
LinkButton lbtnAddtoCart = new LinkButton();
lbtnAddtoCart.ID = "lbtnCart" + i;
lbtnAddtoCart.CommandArgument = i.ToString();
lbtnAddtoCart.CssClass = "glyphicon glyphicon-shopping-cart pull-right";
lbtnAddtoCart.Click+=lbtnAddtoCart_Click;
using (StringWriter sw = new StringWriter())
{
using (HtmlTextWriter html = new HtmlTextWriter(sw))
{
lbtnAddtoCart.RenderControl(html);
}
}
}

convert txt to xml then style with xslt with c# [duplicate]

I want to apply an XSLT Stylesheet to an XML Document using C# and write the output to a File.
I found a possible answer here: http://web.archive.org/web/20130329123237/http://www.csharpfriends.com/Articles/getArticle.aspx?articleID=63
From the article:
XPathDocument myXPathDoc = new XPathDocument(myXmlFile) ;
XslTransform myXslTrans = new XslTransform() ;
myXslTrans.Load(myStyleSheet);
XmlTextWriter myWriter = new XmlTextWriter("result.html",null) ;
myXslTrans.Transform(myXPathDoc,null,myWriter) ;
Edit:
But my trusty compiler says, XslTransform is obsolete: Use XslCompiledTransform instead:
XPathDocument myXPathDoc = new XPathDocument(myXmlFile) ;
XslCompiledTransform myXslTrans = new XslCompiledTransform();
myXslTrans.Load(myStyleSheet);
XmlTextWriter myWriter = new XmlTextWriter("result.html",null);
myXslTrans.Transform(myXPathDoc,null,myWriter);
Based on Daren's excellent answer, note that this code can be shortened significantly by using the appropriate XslCompiledTransform.Transform overload:
var myXslTrans = new XslCompiledTransform();
myXslTrans.Load("stylesheet.xsl");
myXslTrans.Transform("source.xml", "result.html");
(Sorry for posing this as an answer, but the code block support in comments is rather limited.)
In VB.NET, you don't even need a variable:
With New XslCompiledTransform()
.Load("stylesheet.xsl")
.Transform("source.xml", "result.html")
End With
Here is a tutorial about how to do XSL Transformations in C# on MSDN:
http://support.microsoft.com/kb/307322/en-us/
and here how to write files:
http://support.microsoft.com/kb/816149/en-us
just as a side note: if you want to do validation too here is another tutorial (for DTD, XDR, and XSD (=Schema)):
http://support.microsoft.com/kb/307379/en-us/
i added this just to provide some more information.
This might help you
public static string TransformDocument(string doc, string stylesheetPath)
{
Func<string,XmlDocument> GetXmlDocument = (xmlContent) =>
{
XmlDocument xmlDocument = new XmlDocument();
xmlDocument.LoadXml(xmlContent);
return xmlDocument;
};
try
{
var document = GetXmlDocument(doc);
var style = GetXmlDocument(File.ReadAllText(stylesheetPath));
System.Xml.Xsl.XslCompiledTransform transform = new System.Xml.Xsl.XslCompiledTransform();
transform.Load(style); // compiled stylesheet
System.IO.StringWriter writer = new System.IO.StringWriter();
XmlReader xmlReadB = new XmlTextReader(new StringReader(document.DocumentElement.OuterXml));
transform.Transform(xmlReadB, null, writer);
return writer.ToString();
}
catch (Exception ex)
{
throw ex;
}
}
I would like to share this small piece of code which reads from Database and transforms using XSLT. On the top I also have used xslt-extensions which makes it little different than others.
Note: This is just a draft code and may need cleanup before using in production.
var schema = XDocument.Load(XsltPath);
using (var connection = new SqlConnection(ConnectionString))
{
connection.Open();
using (var command = new SqlCommand(Sql, connection))
{
var reader = command.ExecuteReader();
var dt = new DataTable(SourceNode);
dt.Load(reader);
string xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>" + Environment.NewLine;
using (var stringWriter = new StringWriter())
{
dt.WriteXml(stringWriter, true);
xml += stringWriter.GetStringBuilder().ToString();
}
XDocument transformedXml = new XDocument();
var xsltArgumentList = new XsltArgumentList();
xsltArgumentList.AddExtensionObject("urn:xslt-extensions", new XsltExtensions());
using (XmlWriter writer = transformedXml.CreateWriter())
{
XslCompiledTransform xslt = new XslCompiledTransform();
xslt.Load(schema.CreateReader());
xslt.Transform(XmlReader.Create(new StringReader(xml)), xsltArgumentList, writer);
}
var result = transformedXml.ToString();
}
}
XsltPath is path to your xslt file.
ConnectionString constant is pointing to your database.
Sql is your query.
SourceNode is node of each record in source xml.
Now the interesting part, please note the use of urn:xslt-extensions and new XsltExtensions() in above code. You can use this if need some complex computation which may not be possible in xslt. Following is a simple method to format date.
public class XsltExtensions
{
public string FormatDate(string dateString, string format)
{
DateTime date;
if (DateTime.TryParse(dateString, out date))
return date.ToString(format);
return dateString;
}
}
In XSLT file you can use it as below;
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:ext="urn:xslt-extensions">
...
<myTag><xsl:value-of select="ext:FormatDate(record_date, 'yyyy-MM-dd')"/></myTag>
...
</xsl:stylesheet>

Asp.net control to HTML

I'm just trying to get the equivalent HTML code that represent a specific control in asp.
for example i have the following label in ASP
Label x=new Label();
x.ID="a123";
x.Text="b123";
i just want to find a way to get
"<span id='a123'>b123</span>"
You can use this method to render controls to html.
public string RenderControl(Control ctrl)
{
StringBuilder sb = new StringBuilder();
StringWriter tw = new StringWriter(sb);
HtmlTextWriter hw = new HtmlTextWriter(tw);
ctrl.RenderControl(hw);
return sb.ToString();
}
And use
Label x = new Label();
x.ID = "a123";
x.Text = "b123";
var html = RenderControl(x);
will give you <span id="a123">b123</span>

Get div control by name from codebehind

Ok, I want to access div control by id witch is changed dynamically from C# code. Maybe it will be clearer with code:
string divHtml = "";
for (int j = 1; j < 4; j++)
{
string ph = "placeHolder" + j;
Control phd = (Control)FindControl(ph);
StringWriter sw = new StringWriter();
HtmlTextWriter w = new HtmlTextWriter(sw);
phd.RenderControl(w);
divHtml = divHtml + sw.GetStringBuilder().ToString();
}
and ascx part is:
<div runat="server" id="placeHolder1" class="placeholder" >
</div>
It pass compile time but phd is at null value, not to the value of control. It works fine if i access control directly like this:
StringWriter sw = new StringWriter();
HtmlTextWriter w = new HtmlTextWriter(sw);
placeHolder1.RenderControl(w);
divHtml = divHtml + sw.GetStringBuilder().ToString();
Thank you in advance....
FindControl finds only controls in the first level, so if your control is located down in the control tree you need to write your own nested FindControl to make it work.
Have look at ASP.NET Is there a better way to find controls that are within other controls? for more info.
Or if you have the parent (page) it should work to call page.FindControl("placeHolder1") on that control directly.
I figured that it is problem with nesting, thanks to #bang. But since I use master page to display my content, this is solution that is best for me:
for (int j = 1; j < 4; j++)
{
string ph = "placeHolder" + j;
ContentPlaceHolder cph = this.Master.FindControl("MainContent") as ContentPlaceHolder;
Control ctrlPh = cph.FindControl(ph);
StringWriter sw = new StringWriter();
HtmlTextWriter w = new HtmlTextWriter(sw);
ctrlPh.RenderControl(w);
divHtml = divHtml + sw.GetStringBuilder().ToString();
}
Thank you #bang, you pushed me in right direction.

Returning an HtmlTable to be written with ajax

I'd like to programmatically build an HtmlTable/Table in the code behind of a webservice and have it return as a string of HTML so that it can be written with JavaScript to the innerhtml of a span/div/whatever
Something similar to the following:
//webservice.amsx.cs Build the table, called by another/different method
protected string Table_Maker()
{
HtmlTable tbl = new HtmlTable();
HtmlTableCell cell = new HtmlTableCell();
HtmlTableRow row = new HtmlTableRow();
cell.InnerText = "WhateverText";
row.Cells.Add(cell);
tbl.Rows.Add(row);
return tbl.ToString();
}
//somepage.aspx write table to the div
function menuHelper(toplayer, toplayernumber)
{
var sublayertable;
var sublayerpostcompileID;
var toplayernumber;
menuHelper_Part1();
function menuHelper_Part1()
{
//replace ucMainMenu with ucMainMenu_pnlContent
sublayerpostcompileID = toplayer.replace("ucMainMenu", "ucMainMenu_pnlContent");
//Call the webmethod
webbernetz.MenuHelperWebService.Sub_Menu_Helper(toplayernumber, menuHelper_Part2);
}
function menuHelper_Part2(result){
//Write the result to the target area
document.getElementById(sublayerpostcompileID).innerHTML = result;
}
}
When I return it to the javascript the javascript simply writes "System.Web.UI.HtmlControls.HtmlTable".
How di I get it to write the actual table?
The only issue with your code is the use of tbl.ToString().
As noted in some of the other posts, you should Render the table control using an HtmlTextWriter to a StringBuilder object, which can then return a string value for your method. Something like this:
protected string Table_Maker() {
HtmlTable tbl = new HtmlTable();
HtmlTableCell cell = new HtmlTableCell();
HtmlTableRow row = new HtmlTableRow();
cell.InnerText = "WhateverText";
row.Cells.Add(cell);
tbl.Rows.Add(row);
StringBuilder sb = new StringBuilder();
using( StringWriter sw = new StringWriter( sb ) ) {
using( HtmlTextWriter tw = new HtmlTextWriter( sw ) ) {
tbl.RenderControl( tw );
}
}
return sb.ToString();
}
That should return the HTML to be inserted into your page.
The problem here is that the HtmlTable.ToString method that you are using is not appropriate for what you want. 'ToString' returns a String that represents the current Object. In this case you have to Render the table first to an HTMLTextWriter and then you can use the method ToString.
Just use tbl.InnerHtml, instead of ToString
Sounds like you are making it more complicated than it needs to be. How about not using the HtmlTable object and just building a string containing the html you need to output.
There is a RenderControl() method that you can call on any control. Or if you are not using HtmlTable to do anything with it other then building HTML then use HtmlTextWriter.

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