sql connetion in vb.net error message values can't null

Question

0.00/5 (No votes)

See more:

Table Name: Adminlogin

Username Password
Ravi 123
Ramesh 456

Table Definition:

column name Datatype

Username varchar(25) null
Password nvarchar(25)null

My source code:

VB

<pre lang="vb">
Dim con As New SqlConnection("Data Source=D729Z\SQLEXPRESS;Initial Catalog=Franchise;Integrated Security=True")
   Dim da As New SqlDataAdapter
   Dim ds As New SqlDataSource
   Dim cmd As New SqlCommand
   Dim dr As SqlDataReader
   Dim dt As DataTable
   Dim str As String

  str = "select * from Adminlogin where Username='"& UnameTextBox.Text &"',            ' " & UPassword.Text & " ' "

       da = New SqlDataAdapter(str, con)
       cmd = New SqlCommand(str, con)
       da.Fill(dt)
       If dt.Rows.Count < > 0 Then
           Response.Redirect("SelectBranch.aspx")
       Else
           MsgBox(" Username and password invalided ")
       End If
       cmd.ExecuteNonQuery()

       con.Close()</pre>

Run time Error message:

da.fill(dt) is Error point
Value can't be null; Parameter name:dataTable

how can i solve this problem, send related examples are related tutorials

Posted 18-Feb-12 8:00am

Ravi chandran from thanjavur

Add a Solution

3 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2012-02-18T09:59:00

Solution 1

Its is complaining because the parameter you pass to the Fill method is not an instance of a DataTable.
Try changing this line:

VB

Dim dt As DataTable

To this:

VB

Dim dt As New DataTable()

Posted 18-Feb-12 9:59am

OriginalGriff

Comments

Simon_Whale 19-Feb-12 5:54am

Nice spot +5

Simon_Whale · Answer 2 · 2012-02-18T12:12:00

Also the following parts of your code need to be removed as they are doing nothing

VB

cmd = New SqlCommand(str, con)
'
'do other stuff
'
cmd.ExecuteNonQuery()

ExecuteNonQuery is used when you want to execute a query that doesn't return a result set, but rather returns a "number of rows" affected integer

Further reading SqlCommand.ExecuteNonQuery Method[^]

Raimis9 · Answer 3 · 2012-02-19T21:00:00

Solution 3

Your sql statement is not good, please change it to:

VB

str = "select * from Adminlogin where Username='"& UnameTextBox.Text &"' AND Password= ' " & UPassword.Text & " ' "

Posted 19-Feb-12 21:00pm

Raimis9