Dynamic Web Forms

vbFace · January 23, 2004

I am attempting a dynamic web form. I have a table with 4 columns. In each column is a PlaceHolder object. It goes like this:

Column1   Column2          Column3                Column4
------------------------------------------------------------
Labels      RadioBtnLists   ReqFldValidators    TextBoxes

When I dynamically create a Label control, I set the properties like this:

myLabel = new Label
myLabel.ID = "LabelQ" & QNum '<--- Passed Long
myLabel.Text = LabelText
myLabel.BorderStyle = 2
plhLabels.Controls.Add(myLabel) ' Add to the Labels' PlaceHolder

The problem is that the labels all bunch up and continue left-to-right as wide as the table detail (< td >). I tried to add & "< br >< br >" to the myLabel.Text property. It DOES separate the labels, but not exactly in a way that I can control the spacing with the objects in the rest of the Table Row. It is only the text of the control. Its odd.

I am trying to find out how to properly align controls inside the PlaceHolder Object.

Robby · January 23, 2004

I find the best way to place controls on the fly is to use Table/TR/TD tags combined with Styles, whether the styles are in-line or in a CSS file that's up to you.

samsmithnz · January 23, 2004

You you post the table source code? It looks like you may need to specifiy a couple more TD tags...?

vbFace · January 23, 2004

Yes, I am putting all of the like-objects into a placeholder in one table cell. I wouldn't know where to start to mix the creation of dynamic controls with the creation of dynamic table rows.... :( That's what you guys are for! :)

Seriously, I could use help on that. This is the code that I have for the page:

Sub Page_Load

       Dim oConn               as OleDbConnection
       dim oComm               as OleDbCommand
       Dim Reader              as OleDbDataReader
       Dim SQL                 as String
       Dim i                   as Integer

       oConn = MyConn.GetConnection()
       SQL = "SELECT ParentQuestions.QParentText, Questions.QNum, Questions.LabelText, ControlText.ControlText "
       SQL = SQL & "FROM (ParentQuestions INNER JOIN Questions ON ParentQuestions.QParentNum = Questions.QParentNum) 
INNER JOIN ControlText ON Questions.ControlTextID = ControlText.ControlTextID "
       SQL = SQL & "WHERE ParentQuestions.QParentNum = 1;"
       oComm = New OleDbCommand(SQL, oConn)
       Reader = oComm.ExecuteReader()
       i = 1
       While Reader.Read()
           AddControls(i,Reader("Qnum"),Reader("LabelText"))
       End While
   End Sub

   Sub AddControls(Index as Integer, QNum as Long, LabelText as String)

       Dim myLabel     as Label
       Dim myRadio     as RadioButtonList
       Dim myRFV       as RequiredFieldValidator
       Dim myText      as TextBox
       Dim myUnits     as System.Web.UI.WebControls.Unit

       ' Add Label
       myLabel = new Label
       myLabel.ID = "LabelQ" & QNum
       myLabel.Text = LabelText & "<br><br>"
       myLabel.BorderStyle = 2
       plhLabels.Controls.Add(myLabel)

       ' Add Radio
       myRadio = new RadioButtonList
       myRadio.ID = "RadioQ" & Qnum
       myRadio.Items.Add("0")
       myRadio.Items.Add("1")
       myRadio.Items.Add("2")
       myRadio.Items.Add("3")
       myRadio.Items.Add("4")
       myRadio.Items.Add("5")
       myUnits = new System.Web.UI.WebControls.Unit(402)
       myRadio.Width = myUnits
       myRadio.RepeatDirection = 0
       plhRadios.Controls.Add(myRadio)

       ' Add RFV
       myRFV = new RequiredFieldValidator
       myRFV.ID = "RFVQ" & QNum
       myRFV.ErrorMessage = "Unanswered"
       myRFV.ControlToValidate = "RadioQ" & Qnum
       plhRFVs.Controls.Add(myRFV)

   End Sub

<table class="MyText" height="1000" cellspacing="0" cellpadding="1" width="800" bgcolor="white" border="0">
   <tbody>
       <tr>
           <td valign="top" width="800" colspan="9" height="75">
               <!--#include file="include/header.inc"--></td>
       </tr>
       <tr>
           <td class="QText" valign="top" width="800" colspan="9" height="50">
                <br />
               <asp:Label id="lblQParent" runat="server" cssclass="MyText" font-bold="True" forecolor="Blue">Please
                                           indicate the degree to which the following companies provide "value for the cost of
                                           their services."</asp:Label></td>
           </tr>
           <tr>
               <td valign="bottom" width="200" height="25">
               </td>
               <td valign="bottom" align="left" width="67" height="25">
                   <font color="black"><u>No</u>
                   <br />
                   <u>Opinion</u> </font></td>
                   <td valign="bottom" align="left" width="67" height="25">
                   <font color="black"><u>Low </u>
                   <br />
                   <u>Value</u></font>
               </td>
               <td valign="bottom" width="67" colspan="1" height="25">
                   <font color="black"><u>High </u>
                   <br />
                   <u>Value</u></font>
               </td>
               <td width="198" colspan="2">
               </td>
           </tr>
           <tr bgcolor="#e0e0e0">
               <td valign="center" align="left" width="200" height="25">
                    <asp:PlaceHolder id="plhLabels" runat="server"></asp:PlaceHolder>
               </td>
               <td valign="center" width="402" colspan="6" height="25">
                   <asp:PlaceHolder id="plhRadios" runat="server"></asp:PlaceHolder>
               </td>
               <td valign="center" width="100">
                   <asp:PlaceHolder id="plhRFVs" runat="server"></asp:PlaceHolder>
               </td>
               <td valign="center" width="100">
                   <asp:PlaceHolder id="plhQNums" runat="server"></asp:PlaceHolder>
               </td>
           </tr>
           <tr>
               <td valign="center" width="200" height="25">
                    </td>
               <td valign="top" width="402" colspan="6" height="25">
               </td>
           </tr>
           <tr>
               <td colspan="9" height="25">
                    </td>
           </tr>
           <tr>
               <td valign="bottom" align="middle" width="800" colspan="9" height="25">
                    <asp:Button id="btnContinue" onclick="btnContinue_Click" runat="server" Text="Continue"></asp:Button>
                </td>
            </tr>
            <tr>
                <td valign="bottom" width="800" colspan="9">
                    <!--#include file="include/footer.inc"--></td>
            </tr>
        </tbody>
    </table>

Edited January 23, 2004 by vbFace

samsmithnz · January 23, 2004

Thats what I thought. I think that you should look at creating a table cell for each control. Then you'll have better control over alignments and spacing. Its a bit harder to help you more than that, as I'm really not sure what you final end goal is. There are undoubtly going to be exceptions.

vbFace · January 23, 2004

If I want to dynamically add table columns/rows to an HTML table, will I have to incorporate Response.Write("<TR>") and similar .Writes in the code section to build it? I am not sure how to do this.

EDIT: Oh, are you saying abandon the use of the PlaceHolder and dynamically load the controls into the dynamcially created table rows?

samsmithnz · January 23, 2004

I think that dynamically building the table using response.writes or the HTTPStream is a better idea. Then your output will be truely dynamic (that is completely generated on the server).

I wasn't saying that about placeholders, but I do wonder about them (and the person that invented them). You don't really need them, unless you're designing a page and you really do need a placeholder.

mr relaxo · January 23, 2004

Have you considered using the asp:repeater control instead? It seems like it would meet your requirements i.e dynamically create html tables based on a database query and make it alot easier to obtain the properties of the controls. This would also keep alot of presentation logic out of your code.

Just a thought,

best of luck

Kris.

Robby · January 24, 2004

PlaceHolders and Panels are a good idea, however Response.Write is Not. You may want to consider Kris's idea on a Repeater or even a DataList.

samsmithnz · January 24, 2004

PlaceHolders and Panels are a good idea, however Response.Write is Not. You may want to consider Kris's idea on a Repeater or even a DataList.

Robby, you can't say that ("Response.Write is Not") without a reason.

And we still don't have an idea of the scale of the project...?

Robby · January 25, 2004

If the project has more than a single web page than that's scale enough for me. I cannot see any valid reason for using Response.Write aside from doing some lazy debugging (as I sometimes do).

samsmithnz · January 25, 2004

whats so bad about using response.write though?

Why should I use something else? And if response is so bad, should I still be using request too?

Robby · January 25, 2004

Response.Write is slower than using Literals, also, they have no ViewState, literals do.

Derek Stone · January 25, 2004

The problem with Response.Write extends far beyond basic issues such as speed and object persistence. The more important issue is that Response.Write creates spaghetti code-- code that is less readable due to it's spattering across content.

Which is more readable and more manageable?

<script runat="server">
    Private Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs)
         Dim identifier As Integer = 7
         ctlHyperLink.NavigateUrl = "page.aspx?id=" & identifier.ToString()
         ctlHyperLink.Text = "Foobar"
    End Sub
</script>

<asp:HyperLink id="ctlHyperLink" NavigateUrl="" Text="" runat="server" />

<% Dim identifier As Integer = 7 %>
<a href="<% Response.Write("page.aspx?id=" & identifier.ToString()) %>"><% Response.Write("Foobar") %></a>

The latter is clearly a mess.

samsmithnz · January 25, 2004

<% Dim identifier As Integer = 7 %>
<a href="<% Response.Write("page.aspx?id=" & identifier.ToString()) %>"><% Response.Write("Foobar") %></a>

The latter is clearly a mess.

This is all wrong. I'd do it like this: It looks a lot better.

<% Dim identifier As Integer = 7 %>
<a href="page.aspx?id=<%=identifier.ToString()%>">Foobar</a>

This is all wrong. I'd do it like this: It looks a lot better.

I think you'll need a better example than this to convince me. I'd never use response.write like that.

Derek Stone · January 25, 2004

It doesn't matter if you use Response.Write or the "=" shortcut. The point is they both look absolutely horrible. If you have a whole page of these try finding and correcting all of them. Then do the same thing with the preferred method as I posted above.

You need to try it to understand the differences and benefits. It's clear that you won't be convinced otherwise.

samsmithnz · January 25, 2004

Everything in moderation. I don't use comments like response.write or <%=[string]%> in my ASP.NET pages anyway, but when I do, I still think its better to have one simple line , than 4 lines in a script tag. By ASp.NET pages still look neat as and are very maintainable...

Personal judgement.

Derek Stone · January 26, 2004

You don't have 4 lines. You have one per property assignment. I think that's the big point you're missing. You can't include the Page_Load declaration in your argument. It applies only once to all controls on the page.

What if you have logic (If/Then, Do/While, etc.) spattered in inline code tags? Calling that neat would be a complete fallacy. What if your code makes a method call that returns a value? Are you checking the value in inline code? Do you use error handling when it truly needs to be present? Are you properly HTML encoding all entity references and potentially harmful characters (something which Web control properties do for you)?

The list goes on, but I'll leave it at that.

vbFace · January 26, 2004

The scope of the project is a multi-page questionnaire. I will have to look into the data repeater control...

samsmithnz · January 26, 2004

how interesting... I just finished a survey ASP.NET application. It used to be a Delano (bet there aren't many here who know what that is) application, and it used a xsl file to parse the result of an XML file. I've posted the code here, maybe it will interest you...:

<?xml version="1.0"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:template match="/">
<xsl:for-each select="//question[not(section_name = preceding-sibling::question/section_name)]">
<TABLE width="100%" border="1" cellspacing="0" cellpadding="2" align="center" class="verdana" bordercolor="dimgray">
	<TR bgcolor="gainsboro"><TD colspan="9" height="4"><B><xsl:value-of select="section_name"/></B></TD></TR>
	<TR bgcolor="gainsboro">
		<TD height="46" width="1%"> </TD>
		<TD width="64%"><DIV align="center"> </DIV></TD>
           <TD width="7%" bgcolor="whitesmoke"><DIV align="center"><FONT size="2"><I>no data</I></FONT></DIV></TD>
           <TD width="7%"><DIV align="center"><FONT size="2"><I>strongly disagree</I></FONT></DIV></TD>
		<TD width="7%"><DIV align="center"><FONT size="2"><I>disagree</I></FONT></DIV></TD>
           <TD width="7%"><DIV align="center"><FONT size="2"><I>agree</I></FONT></DIV></TD>
		<TD width="7%"><DIV align="center"><FONT size="2"><I>strongly agree</I></FONT></DIV></TD>
	</TR>
	<xsl:call-template name="ordinal_questions">
		<xsl:with-param name="ordinal_section" select="section_name"/>
	</xsl:call-template>
</TABLE>
<BR></BR>
</xsl:for-each>
</xsl:template>

<xsl:template name="ordinal_questions">
<xsl:param name="ordinal_section"/>		
<xsl:for-each select="//question[section_name=$ordinal_section][question_text!=$ordinal_section][question_type='O']">
<TR>
	<TD width="1%" height="46" bgcolor="gainsboro"> </TD>
	<TD width="64%" bgcolor="gainsboro"><xsl:value-of select="question_text"/></TD>
	<TD width="7%" align="center" bgcolor="whitesmoke"><INPUT type="radio" value="0"><xsl:attribute name="name"><xsl:value-of select="controlName"/></xsl:attribute></INPUT></TD>
	<TD width="7%" align="center" bgcolor="gainsboro"><INPUT type="radio" value="1"><xsl:attribute name="name"><xsl:value-of select="controlName"/></xsl:attribute></INPUT></TD>
	<TD width="7%" align="center" bgcolor="gainsboro"><INPUT type="radio" value="2"><xsl:attribute name="name"><xsl:value-of select="controlName"/></xsl:attribute></INPUT></TD>
	<TD width="7%" align="center" bgcolor="gainsboro"><INPUT type="radio" value="3"><xsl:attribute name="name"><xsl:value-of select="controlName"/></xsl:attribute></INPUT></TD>
	<TD width="7%" align="center" bgcolor="gainsboro"><INPUT type="radio" value="4"><xsl:attribute name="name"><xsl:value-of select="controlName"/></xsl:attribute></INPUT></TD>
</TR>
</xsl:for-each>
<xsl:for-each select="//question [section_name=$ordinal_section][question_text!=$ordinal_section][question_type='C']">
<TR bgcolor="gainsboro">
	<TD width="1%" height="46"> </TD><TD><xsl:value-of select="question_text"/></TD>
	<TD width="99%" colspan="6"><textarea rows='3' style='width:100%'><xsl:attribute name="name"><xsl:value-of select="controlName"/></xsl:attribute> </textarea></TD>
</TR>
</xsl:for-each>
<xsl:for-each select="//question [section_name=$ordinal_section][question_text=$ordinal_section]">
<TR bgcolor="gainsboro">
	<TD width="1%" height="46"> </TD>
	<TD width="99%" colspan="6"><B>Comments:</B> (For actionable team feedback, try to structure your comments using the Stop/Start/Continue format)
<BR><textarea rows='3' style="width:100%"><xsl:attribute name="name"><xsl:value-of select="controlName"/></xsl:attribute> </textarea></BR></TD>
</TR>
</xsl:for-each>
</xsl:template>
</xsl:stylesheet>

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