invalid attempt to call checkdataisready when reader is closed

Praveen Kumar

6y7.2kVisual Basic .NET

Hi,

Can someone help me how to fix this problem in vb.net.

Error Message : invalid attempt to call checkdataisready when reader is closed

Private Sub txtBarcode_KeyDown(sender As System.Object, e As System.Windows.Forms.KeyEventArgs) Handles txtBarcode.KeyDown
Try
If e.KeyCode = Keys.Enter Then
con = New SqlConnection(cs)
con.Open()
Dim ctn1 As String = "select * from Company"
cmd = New SqlCommand(ctn1)
cmd.Connection = con
rdr = cmd.ExecuteReader()
If Not rdr.Read() Then
MessageBox.Show("Add company profile first in master entry", "", MessageBoxButtons.OK, MessageBoxIcon.Information)
If (rdr IsNot Nothing) Then
rdr.Close()
End If
Return
End If
If con.State = ConnectionState.Open Then
con.Close()
End If
con = New SqlConnection(cs)
con.Open()
cmd = con.CreateCommand()
cmd.CommandText = "SELECT PID,RTRIM(PurchaseUnit),PurchaseCost,RTRIM(ProductCode),RTRIM(ProductName),SalesCost from Product where Barcode=@d1"
cmd.Parameters.AddWithValue("@d1", txtBarcode.Text)
rdr = cmd.ExecuteReader()
If rdr.Read() Then
lblUnit.Visible = True
txtProductID.Text = rdr.GetValue(0)
lblUnit.Text = rdr.GetValue(1).ToString()
txtPricePerQty.Text = rdr.GetValue(2)
txtProductCode.Text = rdr.GetValue(3).ToString()
cmbProductName.Text = rdr.GetValue(4).ToString()
txtSalesRate.Text = rdr.GetValue(5)
cmbStorageType.SelectedIndex = 0
cmbWarehouse.SelectedIndex = 0
txtQty.Focus()
If (rdr IsNot Nothing) Then
rdr.Close()
End If
End If
If con.State = ConnectionState.Open Then
con.Close()
End If
End If
Catch ex As Exception
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End Sub

8 Replies

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Kelvin Mugambi4y ago
Hello brother...I have the same error when i click a button to load a product in a datagrid. Kindly help me solve it.
+1
Praveen Kumar6y ago
Hi,

I fixed the issue,

Private Sub txtBarcode_KeyDown(sender As System.Object, e As System.Windows.Forms.KeyEventArgs) Handles txtBarcode.KeyDown
Try
If e.KeyCode = Keys.Enter Then
con = New SqlConnection(cs)
Dim ctn1 As String = "select * from Company"
cmd = New SqlCommand(ctn1, con)
con.Open()
rdr = cmd.ExecuteReader()
If Not rdr.Read() Then
MessageBox.Show("Add company profile first in master entry", "", MessageBoxButtons.OK, MessageBoxIcon.Information)
If (rdr IsNot Nothing) Then
rdr.Close()
End If
Return
End If
Dim ctn2 As String = "SELECT PID,RTRIM(PurchaseUnit),PurchaseCost,RTRIM(ProductCode),RTRIM(ProductName),SalesCost from Product where Barcode=@d1"
Dim cmd2 As SqlCommand
Dim rdr2 As SqlDataReader
cmd2 = New SqlCommand(ctn2, con)
cmd2.Parameters.AddWithValue("@d1", txtBarcode.Text)
rdr2 = cmd2.ExecuteReader()
If rdr2.Read() Then
lblUnit.Visible = True
txtProductID.Text = rdr2.GetValue(0)
lblUnit.Text = rdr2.GetValue(1).ToString()
txtPricePerQty.Text = rdr2.GetValue(2)
txtProductCode.Text = rdr2.GetValue(3).ToString()
cmbProductName.Text = rdr2.GetValue(4).ToString()
txtSalesRate.Text = rdr2.GetValue(5)
cmbStorageType.SelectedIndex = 0
cmbWarehouse.SelectedIndex = 0
txtQty.Focus()
If (rdr2 IsNot Nothing) Then
rdr2.Close()
End If
End If
If con.State = ConnectionState.Open Then
con.Close()
End If
End If
Catch ex As Exception
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
End Try
End Sub

+2
Praveen Kumar6y ago
Hi Jignesh,

Good day.

Thank for your reply and with your help i fixed the issue.
+1
Praveen Kumar6y ago
Hi Amit,

Thanks for your help and i fixed the issue.
+1
Amit Gupta6y ago
Please take my words in a positive way and do follow the steps given from 2nd paragraph, it will solves your issue.
+1
Jignesh Kumar6y ago
Hi,

You are closing reader before using it. Please try to close reader once read done,
rdr.Close() need to put proper place.

refer this link,
https://www.vbforums.com/showthread.php?568240-RESOLVED-Invalid-attempt-to-call-MetaData-when-reader-is-closed
+1
Praveen Kumar6y ago
Hi Mr.Amit Gupta,

Good day.

Thanks for your replay.

I believe there is no need to discuss about the coding standard here.
I am looking for solution only and not a comment.
If you are capable give me good solution.

thanks,
+1
Amit Gupta6y ago
Hey

I am not a vb guy but as per error and code review, I am sorry to say your code smells very bad and doesn't follow any coding standards.

Anyway, the error depicts that the reader is closed when you are reading data from it.

Instead of using rdr.Close() everytime, replace it with using block like
using (var rdr=new SqlDataReader) use in vb accordingly
{
.. do your stuff
}

and same applied to SqlConnection object also or its better to create a seperated DataAccess Layer class that do all your suffs neatly
+1