how to Convert string to double

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I have 3 tables one data,sort finalsort.

the columns are lotno,name,type,size(nvarchar)-data, sort and finalsort.

but data is getting inserted in database but showing error as " input string is nt in the correcct format." at line me.finalsorttableadapter.insert/

sometimes error showing as string cannot be converted to double.

in size column i am entering it as 1.2x2.4 and its getting updated in database but showing error in next me.finalsortadapter.insert

actually in 1st form, i am inserting data in database.

in 2nd form, i am retriving data from database through combobox selection.

in 3rd form, again i am retreiving data from form2 and dispalying it in 3rd form.

and the error is showing in 3rd form.

so my values are traversing from table data to sort to finalsort.

can anyone tell me how to convert string to double?

i wrote convert.todouble(textbox4.text) but its not working.

Posted 9-Jul-13 18:16pm

sudeshna from bangkok

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sudeshna from bangkok 10-Jul-13 0:17am

Dim cn As New SqlConnection("Data Source=.\INSTANCE;initial catalog=record;user=sa;password=gariahat")
Dim da As New SqlDataAdapter
Dim cmd As New SqlCommand
Dim ds As New DataSet
'Dim dr As SqlDataReader
cmd.Connection = cn
cn.Open()
'cmd.CommandText = "insert into sort(lot_no,name,type,shape,size,place,weight,issue_dt) values (' " & ComboBox1.Text & " ',' " & TextBox2.Text & " ',' " & TextBox3.Text & " ',' " & TextBox4.Text & " ',' " & TextBox5.Text & " ',' " & TextBox6.Text & " ',' " & TextBox7.Text & " ','" & DateTimePicker1.Value & " ');insert into finalsort(lot_no,name,type,shape,size,place,weight,issue_dt,return_dt) values (' " & ComboBox1.Text & " ',' " & TextBox2.Text & " ',' " & TextBox3.Text & " ',' " & TextBox4.Text & " ',' " & TextBox5.Text & " ',' " & TextBox6.Text & " ',' " & TextBox7.Text & " ',' " & TextBox8.Text & " ',' " & DateTimePicker1.Value & " ')"
cmd.CommandText = "insert into finalsort(lot_no,name,type,shape,size,place,weight,issue_dt,return_dt) values (' " & ComboBox1.Text & " ',' " & TextBox2.Text & " ',' " & TextBox3.Text & " ',' " & TextBox4.Text & " ',' " & TextBox5.Text & " ',' " & TextBox6.Text & " ',' " & TextBox7.Text & " ',' " & Format(CDate(TextBox8.Text), "MM/dd/yyyy") & " ',' " & Format(CDate(DateTimePicker1.Value), "MM/dd/yyyy") & " ')"
cmd.ExecuteNonQuery()
MsgBox("Data successfully added", MsgBoxStyle.Information)

Me.FinalsortTableAdapter.Insert(ComboBox1.Text, TextBox2.Text, TextBox3.Text, TextBox4.Text, TextBox5.Text, TextBox6.Text, TextBox7.Text, Convert.ToDateTime(TextBox8.Text), Format(CDate(DateTimePicker1.Value), "dd/MM/yyyy"))
Me.FinalsortTableAdapter.Fill(Me.RecordDataSet.finalsort)
Me.ComboBox1.Text = ""
Me.TextBox2.Text = ""
Me.TextBox3.Text = ""
Me.TextBox4.Text = ""
Me.TextBox5.Text = ""
Me.TextBox6.Text = ""
Me.TextBox7.Text = ""
Me.TextBox8.Text = ""
Me.DateTimePicker1.Text = ""

this is the code and getting error just after msgbox

ArunRajendra 10-Jul-13 0:22am

I am not sure about your question I am guessing that you are trying to save 1.2x2.4 into the database whose column is double. If its so then its not possible. You need to change the datatype of the field to string.

sudeshna from bangkok 10-Jul-13 0:41am

please can anyone help me.

i will be obliged.
thanks

sudeshna from bangkok 10-Jul-13 0:42am

no, i am column is varchar

sudeshna from bangkok 10-Jul-13 0:43am

and the error showing in table adapter line. my size value is getting inserted in database but showing error when its executing the next line aftr msgbox

sudeshna from bangkok 10-Jul-13 0:44am

Me.FinalsortTableAdapter.Insert(ComboBox1.Text, TextBox2.Text, TextBox3.Text, TextBox4.Text, TextBox5.Text, TextBox6.Text, TextBox7.Text, Convert.ToDateTime(TextBox8.Text), Format(CDate(DateTimePicker1.Value), "dd/MM/yyyy"))

this line showing error that string 2.5x3.5 cant change to double

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Idle_Force · Answer 1 · 2013-07-09T18:25:00

Solution 1

It is better practice to try to parse the string:

VB

Dim dbl As Double
If Double.TryParse(textbox4.Text, dbl) Then
  'use the variable dbl since it has converted
Else 
  'it has not - invalid string format for double
End If

Posted 9-Jul-13 18:25pm

Idle_Force

Comments

sudeshna from bangkok 10-Jul-13 1:09am

actualy nothing is getting inserted in my table adapter.insert. when i am executing from back binding data, no records are showing.

sudeshna from bangkok 10-Jul-13 1:21am

in this line,how do i convert string to double?

Me.FinalsortTableAdapter.Insert(ComboBox1.Text, TextBox2.Text, TextBox3.Text, TextBox4.Text, TextBox5.Text, TextBox6.Text, TextBox7.Text, Convert.ToDateTime(TextBox8.Text), Format(CDate(DateTimePicker1.Value), "dd/MM/yyyy"))

sudeshna from bangkok 10-Jul-13 1:39am

Conversion from string " 2.5x1.2 " to type 'Double' is not valid.

i am getting this error in last form.

but previous form no problem i am facing.

Idle_Force 10-Jul-13 9:31am

That is not a valid double value - cannot convert that.