Update statement for 6 textboxes

Question

5.00/5 (1 vote)

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Hello,

I had created a form in ASP and created a database. Every thing is ok but when I am updating it, like if I am updating any one text box and left the rest blank then it will be updated as the fields blank in the database, but i want to be updated to only that field.Now it showing exceptional error as ""Must declare the scalar variable "@firstname".""
please help me

C#

protected void Btndisplay_Click(object sender, EventArgs e)
        {
            sd.UpdateCommand = new SqlCommand("update formtest set firstname=@firstname, username=@username, pass=@pass, email_id=@email_id where ID=@ID", conn);
            if (!string.IsNullOrEmpty(Tbfname.Text))
            {
                sd.UpdateCommand.Parameters.AddWithValue("@firstname", Tbfname.Text);
            }
            if (!string.IsNullOrEmpty(TbUname.Text))
            {
                sd.UpdateCommand.Parameters.AddWithValue("@username", TbUname.Text);
            }
            if (!string.IsNullOrEmpty(TbPass.Text))
            {
                sd.UpdateCommand.Parameters.AddWithValue("@pass", TbPass.Text);
            }
            if (!string.IsNullOrEmpty(Tbemail.Text))
            {
                sd.UpdateCommand.Parameters.AddWithValue("@email_id", Tbemail.Text);
            }
            if (!string.IsNullOrEmpty(Tbid.Text))
            {
                sd.UpdateCommand.Parameters.AddWithValue("@ID", Convert.ToInt32(Tbid.Text));
            }
            conn.Open();
            sd.UpdateCommand.ExecuteNonQuery();
            conn.Close();
         }

sd.UpdateCommand.Parameters.Add("@firstName", string).Value(Tbfname.Text); WHEN I ADD THIS IT SHOWING INVALID expression string

Posted 3-Jun-12 6:03am

selflearning

Updated 3-Jun-12 7:44am

v4

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3 solutions

Solution 3

Ohh, nice! Absolutely no validation at all, and on top of that, you're letting the users input ID values, meaning that ANY USER can change the account details (AND PASSWORD) of ANY user account in your system!

I can see good times ahead for you!

Posted 3-Jun-12 7:46am

Dave Kreskowiak

Comments

selflearning 3-Jun-12 15:22pm

Thanks for your reply.. its just a simple CRUD nothing else is over and coming to the validations how can you show that one in coding. I know I am having a very good time and thanks for your suggestion.

Solution 4

you can create your query as follows

C#

string sqlQuery="update formtest set ";
if(!string.IsNullOrEmpty(Tbfname.Text))
{
 sd.UpdateCommand.Parameters.AddWithValue("@firstname", Tbfname.Text);

sqlQuery = sqlQuery +" firstname=@firstname"
}

now use your logic to create your query with all textboxes. than in which textbox you enter data only which data will update rest will remain unupdated.

Posted 4-Jun-12 1:46am

Prosan

Comments

selflearning 5-Jun-12 7:27am

Thanks for your valuable reply but still it giving the exception error...

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taha bahraminezhad Jooneghani · Accepted Answer · 2012-06-03T06:15:00

Solution 1

check the value of text boxes

C#

if(!string.IsNullOrEmpty(Tbfname.Text))
{
 sd.UpdateCommand.Parameters.AddWithValue("@firstname", Tbfname.Text);
}

do this for each text box!

Posted 3-Jun-12 6:15am

taha bahraminezhad Jooneghani

Comments

VJ Reddy 3-Jun-12 12:25pm

Good answer. 5!

selflearning 3-Jun-12 12:30pm

It showing exceptional error as "Must declare the scalar variable "@firstname"."