ASP.NET Programming tips

In this Article, I will provide a few tips in problem and solution manner.

Opening an ASPX page in Visual studio 2003 is very slow.

To make it fast, please do follow below steps:  



Double clicking an ASPX page will now open faster.

Remembering connection string is difficult.

No need to remember the connection string. Follow below steps:

Don’t know the namespace for a particular class in Visual studio 2005.

You know the class name but not sure in which namespace it resides? (Say for Example NameValueCollection)

Your child ASPX page is not getting refreshed properly.

You might have opened a child page using window.open or some other method and passed some data from the parent page to the child page using QueryString for example. Subsequently, the child page may not populate the data based on the values passed by parent page. This is because the data passed is cached in the child browser. This could be avoided by passing Random value (e.g., querystring = querystring + “&Random=” + Math.random()) as one of the argument in query string. This will refresh the child page each time.

Need to share values between parent and child page in JavaScript.

Sometimes you may load child pages (using iFrame or Tab) in parent page. The value can be shared easily between parent and child pages using global variables in parent page. The variable can be accessed in child page using:

parent.VariableName
                      

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Blob values may be stored in SQL as byte array and you need the corresponding Text for that.

Use the query:

select convert (varchar (max), BlobFieldName) from TableName where [Condition]
                      

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Need to find out the protocol correctly of your page.

The serverside approach (Request.Url) to find out the protocol in a website (HTTP or HTTPS) may be error prone on a production server. This could be resolved using Clientside code (JavaScript)   window.location.href will give the full path of the requested file. We could parse and get the protocol from the above value.

Need to toggle between ASPX page blocks in client side.

 // It will hide the controls specified in the id
                      document.getElementByID (‘id’).style.display = “none”; 
                      // It will show the controls specified in the id
                      document.getElementByID (‘id’).style.display = “block”;  
                      

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Need to add a JavaScript element dynamically in an ASPX page.

function CreateElement (ele)
                      {
                         var e = document.createElement(ele);
                         e.[Attribute1] = [Value1];
                         e.[Attribute2] = [Value2];
                         // This can be changed wherever you like to append the created element 
                         document.getElementsByTagName("head")[0].appendChild(e); 
                      }
                      

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Need to show print dialog without showing the content page to the user.

       

On a button click we need to show only the print dialog not the content page. This can be accomplished using iFrame in client side.

1. Have the ASPX page that having the content to be printed (e.g., PrintPage.aspx). This page should call window.print() in its client side to launch the print dialog.

2. Do include (in the parent ASPX page):

<ifame id=”frmPrint” src=”javascript:return false;”></iframe>
                      

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3. In the onload event of Parent page hide the iFrame using:

document.getElementByID (‘frmPrint’).style.display = “none”;
                      

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4. In the click event of the Print button write below code:

//Show the iFrame
                      document.getElementByID (‘frmPrint’).style.display = “block”; 
                      //Load the page to launch the print dialog
                      document.getElementByID (‘frmPrint’).src = “PrintPage.aspx”; 
                      //Hide the iFrame
                      document.getElementByID (‘frmPrint’).style.display = “none”; 
                      

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The list can include much more. I’ll explain some in more details in forthcoming articles.

Thanks for reading!