CODEWITHSUNDEEP
c#asp.netc#-4.0
Mark Allison
Mark Allison

Reputation: 7228

Programmatically change background colour of some text

I have implemented master pages using this example How to implement a status bar in an ASP.NET application?. I have a property on my SiteMaster.cs inherited MasterPage called Environment. On my MasterPage.master I have this code:

<body>
    <form id="frmMaster" runat="server">
        <.. some content removed for brevity ...>

        Environment: <%= this.Environment %>
    </form>
</body>

What I would like to do is evaluate this.Environment and if it is "LIVE" then colour the background of this.Environment text red, and if it's "TEST" colour it yellow. How would I do this?

UPDATE I've just added this code to MasterPage.master

protected void Page_Load(object sender, EventArgs e)
{
    lblEnvironment.Text = this.Environment;
    if (this.Environment == "LIVE")
    {
        lblEnvironment.BackColor = System.Drawing.Color.Red;
    }                
}

The page loads, but the text does not get set, it's blank! Also the old text, that was populated is now blank too (I left the old code there for now). I also get a warning in Visual Studio:

'ASP.masterpage_master.Page_Load(object, System.EventArgs)' hides inherited member 'SiteMaster.Page_Load(object, System.EventArgs)'. Use the new keyword if hiding was intended.

UPDATE2: This is what I have in SiteMaster.cs

using System;
using System.Web.UI;

public class SiteMaster : MasterPage
{
    public string StatusText { get; set; }
    public string StatusTime { get; set; }
    public string Environment { get; set; }

    protected virtual void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            if (Session["status"] != null)
            {
                this.StatusText = Session["status"].ToString();
                this.StatusTime = Session["statusTime"].ToString();
            }

            this.Environment = Session["environment"].ToString();
        }

    }
}

Upvotes: 0

Views: 5363

Answers (3)

Shadow Wizard
Shadow Wizard

Reputation: 66389

You can also move the code from Page_Load to Page_PreRender in MasterPage.master and it should work.. it was blank because MasterPage.master Page_Load overwritten the Page_Load of SiteMaster.Master thus Environment was never assigned.

Upvotes: 1

Graham Clark
Graham Clark

Reputation: 12966

Instead of using the <%= syntax to print out the environment (this is using Response.Write), consider using a server control like a Literal or a Label. As you want to change the background colour, this suggests styling (CSS), so a Label would be appropriate.

(A Literal is just a text placeholder and renders no HTML, whereas a Label (usually) renders the text inside <span> tags.)

So I would change your master page markup to

Environment: <asp:Label ID="environmentLabel" runat="server" />

In the code-behind, set the Text property of environmentLabel to this.Environment. At the same time, test the value of the evironment, and set the BackColor property of the label as appropriate (or apply a CSS class).

UPDATE:
For a master page, you just need one class, which will inherit from System.Web.UI.MasterPage. If you create this in Visual Studio and call it SiteMaster, you'll get 3 files:

SiteMaster.Master (the markup)
SiteMaster.Master.cs (the code-behind)
SiteMaster.Master.designer.cs (automatically generated/updated)

In the SiteMaster.Master file, you'll want something like this:

<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="SiteMaster.master.cs" Inherits="WebApplication1.SiteMaster" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <asp:ContentPlaceHolder ID="head" runat="server">
    </asp:ContentPlaceHolder>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Label ID="environmentLabel" runat="server" />

        <asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server" />
    </div>
    </form>
</body>
</html>

In SiteMaster.Master.cs, you'll need something like this:

using System;

namespace WebApplication1
{
    public partial class SiteMaster : System.Web.UI.MasterPage
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            this.environmentLabel.Text = "environment";
            this.environmentLabel.BackColor = System.Drawing.Color.Red;
        }
    }
}

As the environment label is on the master page, any normal page (ASPX) using this master page will get the label displayed. Every time a page is loaded, the Page_Load event in SiteMaster.Master.cs will be called, and the text will be updated. You don't need to define the MasterPage class yourself, that's provided by the .NET framework.

You may want to improve this Page_Load method, either by using ViewState and therefore only setting the text if you're not doing a PostBack, or by disabling ViewState on the environmentLabel control.

Finally, you'll have one or more ASPX pages in your site, with something like this at the top of the markup:

<%@ Page Title="" Language="C#" MasterPageFile="~/SiteMaster.Master" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="WebApplication1.WebForm1" %>

Upvotes: 3

RameshVel
RameshVel

Reputation: 65867

something like this.. 

   var preTag = @" <font style=""background:yellow;color:#ff0000;font-weight:600;""><b>";
   var postTag = " </b></font>";

   Environment: <%= ((this.Environment=="LIVE") ? (preTag + this.Environment + postTag) : this.Environment)   %>

Upvotes: 1

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