CODEWITHSUNDEEP
sqlvb.netwinforms
vimal vasudevan
vimal vasudevan

Reputation: 179

datatable row count shows 1 even when there are no records present

I am returning the retrieved value into a variable but after checking whether the rows exist or not. But the if condition fails as there are currently no records in the table.

    Dim sqlstr as string
    Dim da As SqlClient.SqlDataAdapter
    sqlstr = "select max(mat_req_no) as mat_req_no from pos_mrq_hdr"

    If dt.Rows.Count > 0 Then
        ltino = dt.Rows(0)("mat_req_no").tostring

    End If


    the if dt.rows.count > 0

Upvotes: 1

Views: 1516

Answers (1)

Maadh
Maadh

Reputation: 633

you may forget some statements in your code , But when I test in Max it will return always (1) in row count so we should test returned value if NULL or NOT

the complete code will be 

Imports System.IO
Imports System.Data.SqlClient
Public Class Form1
Dim cnn As SqlConnection
Dim connectionString As String
Dim sqlAdp As SqlDataAdapter
Dim ds As New DataSet
Dim dt As New DataSet

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
     connectionString = "Data Source=servername; Initial Catalog=databasename; User ID=userid; Password=password"
    cnn = New SqlConnection(connectionString)
    cnn.Open()
    sqlAdp = New SqlDataAdapter("select max(mat_req_no) as mat_req_no from pos_mrq_hdr", cnn)
    cnn.Close() 'connection close here , that is disconnected from data source
    sqlAdp.Fill(ds)
    sqlAdp.Fill(dt)
    'fetching data from dataset in disconnected mode
    ' MsgBox(ds.Tables(0).Rows.Count)
    If IsDBNull(ds.Tables(0).Rows(0).Item(0)) Then
        '    MsgBox("no")
    Else
        Dim ltino = ds.Tables(0).Rows(0)("mat_req_no").ToString
        '  MsgBox(ltino)
    End If
End Sub
    End Class

Upvotes: 1

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