guys..i got a lilttle problem with my code,can anyone help

King Umar

11y1.4kC# Corner

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim myconnection As New SqlConnection

myconnection.ConnectionString = "Data Source=USER-PC;Initial Catalog=MiSInventory;Integrated Security=True"

Dim READER As SqlDataReader

Try

myconnection.Open()

Dim Query As String

Query = "SELECT COUNT(DISTINCT Category)AS NumCount FROM ItemAdd GROUP BY Category"

READER = Command.ExecuteReader

Command = New SqlCommand(Query, myconnection)

nDataAdapter = New SqlDataAdapter(Command)

ds = New DataSet()

nDataAdapter.Fill(ds)

TextBox1.Text = "ds.Tables[0].Rows[1][NumCount].ToString()"

MessageBox.Show("Data will be count")

myconnection.Close()

Catch ex As Exception

MessageBox.Show("Could not connect database: " & ex.Message, "Database Connection Error", MessageBoxButtons.OK, MessageBoxIcon.Error)

Finally

myconnection.Dispose()

End Try

End Sub

When i click the button count it says "object reference not set to an instance of an object"

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

Rafnas T P9y ago
try replacing TextBox1.DataBindings.Add("text", ds.Tables("ItemAdd"), "Category")
with
TextBox1.Text = ds.Tables[0].Rows[0][0].ToString()
0
King Umar11y ago
Dim ds As New DataSet

Dim sqlconn As New SqlConnection
sqlconn.ConnectionString = "Data Source=USER-PC;Initial Catalog=MiSInventory;Integrated Security=True"
Dim READER As SqlDataReader
Dim nDataAdapter As DataAdapter

Try
sqlconn.Open()
Dim Query As String
Query = "SELECT COUNT(DISTINCT Category) AS NUMCOUNT FROM ItemAdd GROUP BY Category"
Command = New SqlCommand(Query, sqlconn)
nDataAdapter = New SqlDataAdapter(Command)
ds = New DataSet("ItemAdd")
nDataAdapter.Fill(ds)

TextBox1.DataBindings.Add("text", ds.Tables("ItemAdd"), "Category")

nDataAdapter.Dispose()
Command.Dispose()

MessageBox.Show("Data will be count")

Catch ex As Exception
MessageBox.Show("Could not connect to database: " & ex.Message, "Database Connection Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
Finally
End Try

sqlconn.Close()
End Sub
got error said that :Value cannot be null and Parameter name:data source <--- can anyone help a newbie like me..huhu
0
Saroj Kumar Sahu11y ago
Hi,
Please check with the line of code from where you are fetching and assigning to text box

TextBox1.Text = "ds.Tables[0].Rows[1][NumCount].ToString();

Before assigning , check that value of dataset is null or not.
+1
Upendra Pratap Shahi11y ago
debug your code and check whether an object get null value.
+1
King Umar11y ago
can you tell more about it sir,i'm just a beginner
0
Upendra Pratap Shahi11y ago
Hint: I your code there is some object which is NULL. and you will be trying to read some property value of that object.
+1