UPDATE statement doesn't work

Question

2.25/5 (4 votes)

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Hello.

I have 1 textbox, 1 button, and 1 SQL database.

I need update the database content with the textbox, but doesn't work.

What I can do?

The table:

<br />
|  ID  |  PagePath  |  PageName  |  PageContent  |<br />
|auto| varchar | varchar | varchar |<br />
<br />
| 1 | StartPage | Start | <h1>Hello!</h1> |

The code:

C#

protected void BtnUpdate_Click (object sender, EventArgs e)
{
   UpdateContent("StartPage","Start",TxtBoxEdit.Text);
}

private void UpdateContent(string PagePath, string PageName, string NewText)
{
    SqlCommand EditPage = new SqlCommand(
       "UPDATE Pages SET PageContent='" + NewText +
       "' WHERE PagePath='" + PagePath + "' AND PageName='" + PageName + "'", DBConnection);
            DBConnection.Open();        
            EditPage.ExecuteNonQuery();
            DBConnection.Close();
}

Posted 28-Feb-12 8:02am

TANicox

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Comments

ZurdoDev 28-Feb-12 14:07pm

Do you get an error? Have you done a SQL trace to see what is happening?

TANicox 28-Feb-12 14:19pm

no, just dont update

ZurdoDev 28-Feb-12 14:20pm

Then do a SQL trace because likely your WHERE statement is not finding a match.

Dean Oliver 28-Feb-12 14:18pm

What is the exact error you are getting?

TANicox 28-Feb-12 14:28pm

there is not an error

Kschuler 28-Feb-12 14:19pm

What's the error message? How are you setting your connection?

TANicox 28-Feb-12 14:29pm

That's the connection setting:

SqlConnection DBConnection = new SqlConnection(@"Data Source=.\SQLEXPRESS;AttachDbFilename=~\App_Data\SAFA.mdf;Integrated Security=True;User Instance=True");

Dean Oliver 28-Feb-12 14:46pm

Is the BtnUpdate_Click event been fired? When you click the button. Put a breakpoint on the event as well as the UpdateContent() method

TANicox 28-Feb-12 16:10pm

The problem is in the TextBox, because I have changed the TextBox for a label and it works.

Do you have some idea of what the problem is?

Sudip Saha 1-Mar-12 3:40am

use TxtBoxEdit.Text.Trim()

6 solutions

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Dean Oliver · Answer 1 · 2012-02-28T09:04:00

C#

string commandText = "UPDATE Pages SET PageContent = @pc WHERE PagePath=@pp AND PageName=@pn";

   using (SqlConnection connection = new SqlConnection(connectionString))
   {
       SqlCommand command = new SqlCommand(commandText, connection);
       command.Parameters.Add("@pp", SqlDbType.NVarChar);
       command.Parameters.Add("@pn", SqlDbType.NVarChar);

       // Use AddWithValue to assign values.

       command.Parameters.AddWithValue("@pc", NewText);

       try
       {
           connection.Open();
           Int32 rowsAffected = command.ExecuteNonQuery();
           Console.WriteLine("RowsAffected: {0}", rowsAffected);
       }
       catch (Exception ex)
       {
           Console.WriteLine(ex.Message);
       }

Mohammad A Rahman · Answer 2 · 2012-02-29T21:31:00

Solution 6

By looks of your table data, I am guessing your are trying to enter HTML tag inside the TextBox and grab those to save into DB.

You might need to use following method[^] to get the contents of TextBox and then write that back to the DB.

Hope it helps :)

Posted 29-Feb-12 21:31pm

Mohammad A Rahman

Shameel · Answer 3 · 2012-02-28T08:44:00

Solution 1

Assign you update command to a string variable and check it's value during debugging. It seems your update statement's WHERE clause has no rows to update. That's why you don't see any error and still no rows are updated.

Posted 28-Feb-12 8:44am

Shameel

Comments

Oshtri Deka 28-Feb-12 15:11pm

Sounds reasonable.

OriginalGriff · Answer 4 · 2012-02-28T08:47:00

You do realise how dangerous that is, don't you?
Do not concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

The original problem is probably that you need to change your connection string:

AttachDbFilename=~\App_Data\SAFA.mdf

May be the problem. Try changing it to use Server.MapPath to change teh "~" into a "normal" file path specification.

But seriously, use parametrized queries - a four character sequence typed in the textbox will destroy your entire database table!

Photon_ · Answer 5 · 2012-02-29T21:11:00

Solution 5

if you are not getting error then
it may possible it is not finding the field according to your search
your text is being changed due to page script check enable i
think if you will update without script then it will update
enter a simple text it will work

Posted 29-Feb-12 21:11pm

Photon_

TANicox · Answer 6 · 2012-03-01T06:15:00

Solution 7

The problem was in the Page_Load

When the page loaded, the control loading the text in the database, so when I pressed the button the value backs to default.

I use an

C#

if (!Page.IsPostBack)

to change that, and it's works

Thanks everyone for help

Posted 1-Mar-12 6:15am