Differences between SqlDataAdapter and SqlDataReader

When I went for an interview last few weeks, the interviewers threw me some technical questions about .NET. Luckily I still can get some correct ideas on those questions. Here I will share with you one of the interview questions "What is the differences between SqlDataAdapter and SqlDataReader?"

For SqlDataReader, you need to call the ExecuteReader method of the SqlCommand object.

You can use SqlDataReader when your data access operations is mainly for fetching and displaying all the records in the database, which does not involve insert, update or delete actions, and other manipulations actions e.g. forward-only and read-only.

If the data from database is mainly for displaying in data grid, labels or other web controls, you can go for SqlDataReader.

However, when the SqlDataReader is in use, it requires the connection with the database remains open until its operation is completed.

In short, SqlDataReader can be used when:
- To deal with large volumes of data
- To optimize data access
- To display data in web controls (no update/insert/delete action)


SqlDataAdapter acts as a bridge between a dataset and database server for fetching and saving data. If your data access operations involve actions other than only displaying data, you can use SqlDataAdapter to generate a dataset or datatable.

By using SqlDataAdapter, you don’t need to explicitly open the connection. It will open and close the connection automatically when required.

One of the advantages is that the dataset works on a disconnected architecture. The connection does not need to be remained for it to perform manipulations or other actions. The connection is only required when there is an update records to the database server.

Hope you can get some ideas about SqlDataReader and SqlDataAdapter.

Disable Right-Click for Your Website

NO RIGHT-CLICK for Images
Have you ever tried so hard on your website to stop someone stolen your graphics as their own.

Here is an extra step in protecting your graphics/images from being saved. But there is no foolproof method to stop someone from copy your images. If they really want something from your web site, they can find ways around it. But at least you can eliminate some proportion of visitors stealing images from your web site.

It is very simple. Whenever someone right clicks his/her mouse, a message will popped up to show him/her that he/she do not have permission to do so. Place the script below within the head tags of your html.

<script language="JavaScript">
<!--
var msg="Right-click is disabled!";

function rightclick(go) {
    if (document.all) {
        if (event.button == 2) {
            alert(msg);
            return false;
        }
    }
    if (document.layers) {
        if (go.which == 3) {
            alert(msg);
            return false;
        }
    }
}
if (document.layers) {
    document.captureEvents(Event.MOUSEDOWN);
}
document.onmousedown=rightclick;
// -->
</script>

NO RIGHT-CLICK for Sources
To protect the whole page of your web site, copy and paste the script below within your head tags in your html.

<script language="JavaScript">
<!--
function rightclick(e) {
    if (navigator.appName == 'Netscape' && (e.which == 3 || e.which == 2))
        return false;
    else if (navigator.appName == 'Microsoft Internet Explorer' && (event.button == 2 || event.button == 3)) {
        alert('Right-click is disabled!');
        return false;
    }
    return true;
}

document.onmousedown=rightclick;
document.onmouseup=rightclick;
if(document.layers) window.captureEvents(Event.MOUSEDOWN);
if(document.layers) window.captureEvents(Event.MOUSEUP);
window.onmousedown=rightclick;
window.onmouseup=rightclick;
//-->
</script>


Remove a Visual Studio from Source Control

To remove an item from source control, the first thing that you need to do is to select all items in your project and uncheck the Read-Only property. Click Apply then OK. Do these steps for both folder of your project (MyDocuments\Visual Studio Projects and wwwroot).


In your Solution Directory, delete all the files with the extension .vssscc or .scc (includes all child folders in your solution directory).

Next, right click on your .sln file and select Open with… Select Notepad.

In your .sln file, find the GlobalSection(SourceCodeControl) = preSolution part. Select the whole part of it until EndGlobalSolution and remove it. Save and close the file.


For each of the .vbproj in your project, open it with Notepad. Under <VisualBasic> you can find the following attributes: SccProjectName, SccLocalPath, SccAuxPath, and SccProvider as shown below. Remove it, save and close the file.


Now, the source control had completely removed from the project.

Hope you will find this helpful.

Add a Drop Down List into Excel File using C# .NET

Here I will demonstrate to you how to add a drop down list into an Excel File using C# .NET. Before you adding this codes, make sure you have add the Microsoft Excel Object Library as reference into your project.

Here are the codes:

Excel.Application xlsApp = new Excel.ApplicationClass();
Excel.Workbook xlsWorkbook;
Excel.Worksheet xlsWorksheet;
object oMissing = System.Reflection.Missing.Value;

//Create new workbook
xlsWorkbook = xlsApp.Workbooks.Add(true);

//Get the first worksheet
xlsWorksheet = (Excel.Worksheet)(xlsWorkbook.Worksheets[1]);

string[] ddl_item ={"Answers","Autos","Finance","Games","Groups","HotJobs","Maps","Mobile Web","Movies","Music","Personals","Real Estate","Shopping","Sports","Tech","Travel","TV","Yellow Pages"};

Range xlsRange;
xlsRange = xlsWorksheet.get_Range("A1","A1");

Excel.DropDowns xlDropDowns;
Excel.DropDown xlDropDown;
xlDropDowns = ((Excel.DropDowns)(xlsWorksheet.DropDowns(oMissing)));
xlDropDown=xlDropDowns.Add((double)xlsRange.Left,(double)xlsRange.Top,(double)xlsRange.Width,(double)xlsRange.Height,true);

//Add item into drop down list
for (int i=0;i<ddl_item.length;i++) {
    xlDropDown.AddItem(ddl_item[i],i+1);
}

xlsApp.DisplayAlerts = false;
xlsWorkbook.Close(true, filename, null);
xlsApp.Quit();

xlsWorksheet = null;
xlsWorkbook = null;
xlsApp = null;

Cheers!

Add a Project or Solution to Source Control

You can add projects and solutions to source control through Solution Explorer in Visual Studio. Follow the steps as below:

1. On the Tools menu, click Options. In the Options dialog box, select Source Control. Select Visual Studio Team Foundation Server from the Current source control plug-in list.

2. In Solution Explorer, right-click the solution, choose Add Solution to Source Control.


3. In the Add Solution to Source Control dialog box, navigate to where you want to add the project or solution. You can either accept default values, or click Make New Folder and enter the desired folder name.

4. Click OK.

15 Date Formats in SQL Server 2000

--'YYYYMMDD'
SELECT CONVERT(CHAR(8), GETDATE(), 112)
--'YYYY-MM-DD'
SELECT CONVERT(CHAR(10), GETDATE(), 23)
--'YYYY-MMM-DD'
SELECT STUFF(CONVERT(CHAR(10), GETDATE(), 23), 6, 2, LEFT(DATENAME(m, GETDATE()), 3))
--'YYMMDD'
SELECT CONVERT(VARCHAR(8), GETDATE(), 12)
--'YY-MM-DD'
SELECT STUFF(STUFF(CONVERT(VARCHAR(8), GETDATE(), 12), 5, 0, '-'), 3, 0, '-')
--'YY-MMM-DD'
SELECT STUFF(STUFF(STUFF(CONVERT(VARCHAR(8), GETDATE(), 12), 3, 2, LEFT(DATENAME(m, GETDATE()), 3)), 6, 0, '-'), 3, 0, '-')
--'MM-DD-YY'
SELECT CONVERT(CHAR(8), GETDATE(), 10)
--'MMDDYY'
SELECT REPLACE(CONVERT(CHAR(8), GETDATE(), 10), '-', SPACE(0))
--'MM/DD/YY'
SELECT CONVERT(CHAR(8), GETDATE(), 1)
--'MM/DD/YYYY'
SELECT CONVERT(CHAR(10), GETDATE(), 101)
--'DD-MM-YY'
SELECT REPLACE(CONVERT(CHAR(8), GETDATE(), 3), '/', '-')
--'DD-MMM-YY'
SELECT STUFF(REPLACE(CONVERT(CHAR(8), GETDATE(), 3), '/', '-'), 4, 2, LEFT(DATENAME(m, GETDATE()), 3))
--'DDMMYY'
SELECT REPLACE(CONVERT(CHAR(8), GETDATE(), 3), '/', SPACE(0))
--'DD/MM/YY'
SELECT CONVERT(CHAR(8), GETDATE(), 3)
--'DD/MM/YYYY'
SELECT CONVERT(CHAR(10), GETDATE(), 103)

Hope this will help. Cheers!