how to subtract a value from database with a value from text

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• 

  Amitesh Verma11y agoPosted Aug 6, 2015, 3:30 AM

  Accepted answer

  string txtvalue=txtbox.text;

   

  string query="Select amount from table";

  datatable dt=new datatable;

   after this ,get the amount value in

  string newamount=dt.rows[0]["amount"].tostring();

   

  now subtract:

  string subtractdata=txtvalue-newamount;

   

   
• 

  King Umar11y agoPosted Aug 6, 2015, 4:02 AM

  okay (Y)
   :D
• 

  Amitesh Verma11y agoPosted Aug 6, 2015, 3:52 AM

  yab fine with that ,you can use this like this

   

  select columnname from table where condtioncolumn='"+textbox1.text+"';
• 

  Rajeesh Menoth11y agoPosted Aug 6, 2015, 3:51 AM

  Hi,

   

  Welcome  King Umar :)

   

  Correct one.. Use + don't use &

   

  "select Quantity FROM [AddItem] WHERE ='" + TextBox1.Text + " ' " 
• 

  King Umar11y agoPosted Aug 6, 2015, 3:49 AM

  thanks a lot  Amitesh and Rajeesh ,i have another question,
  how if i want to specified the sql command,for example i put a 'WHERE' condition on the sql command like "select Quantity FROM [AddItem] WHERE ='" & TextBox1.Text & " ' "
  
  is this are correct or not ?
• 

  Rajeesh Menoth11y agoPosted Aug 6, 2015, 3:36 AM

  Hi,

   

   

  Private Sub TextBox6_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox6.TextChanged

  Dim value1, value2 As Integer

  If Integer.TryParse(TextBox1.Text, value1) Then

  If Integer.TryParse(TextBox6.Text, value2) Then

  TextBox11.Text = (value1 - value2).ToString()

  End If

  End If

  End Sub

   

  Ref  : https://social.msdn.microsoft.com/Forums/en-US/db46cc77-2d38-4b2e-b0a2-2a364686c291/subtract-two-value-intextboxs?forum=vblanguage