Updating data in gridview using vb.net - vb.net

Question

First I populated the datagridview by data of sqlserver 2008 database table, now i have muliple rows in datagridview containing data, i am trying to update any row but, in the database table it replaces other rows data by the row data that iam trying to update
the code for update statement is given below
Plz help me
Dim cmd As New SqlCommand("Update EmployeeDetail Set Salary = '" &
dgvEmpDetail.Rows(0).Cells(1).Value & "', Experience ='" &
dgvEmpDetail.Rows(0).Cells(2).Value & "', Skills='" &
dgvEmpDetail.Rows(0).Cells(3).Value
& "' where Emp_ID = '" & dgvEmpDetail.Rows(0).Cells(0).Value & "'", con)
con.Open()
cmd.ExecuteNonQuery()
con.Close()

Answer 1

You've hard coded the row - dgvEmpDetail.Rows(0).
I imagine you are calling this in a loop. You should do something like:
For i As Integer = 0 To dgvEmpDetail.Rows.Count - 1
Dim cmd As New SqlCommand("Update EmployeeDetail Set Salary = '" & dgvEmpDetail.Rows(i).Cells(1).Value & "', Experience ='" & dgvEmpDetail.Rows(i).Cells(2).Value & "', Skills='" & dgvEmpDetail.Rows(i).Cells(3).Value()& "' where Emp_ID = '" & dgvEmpDetail.Rows(i).Cells(0).Value & "'", con)
con.Open()
cmd.ExecuteNonQuery()
con.Close()
Next
Your code is susceptible to SQL injection. You should put the update SQL in to a stored procedure - its faster and safer!

Answer 2

Protected Sub Page_Load()
If Not Page.IsPostBack Then
' Create a new table.
Dim taskTable As New DataTable("TaskList")
' Create the columns.
taskTable.Columns.Add("Id", GetType(Integer))
taskTable.Columns.Add("Description", GetType(String))
taskTable.Columns.Add("IsComplete", GetType(Boolean))
'Add data to the new table.
For i = 0 To 19
Dim tableRow = taskTable.NewRow()
tableRow("Id") = i
tableRow("Description") = "Task " + i.ToString()
tableRow("IsComplete") = False
taskTable.Rows.Add(tableRow)
Next
'Persist the table in the Session object.
Session("TaskTable") = taskTable
'Bind data to the GridView control.
BindData()
End If
End Sub
Protected Sub TaskGridView_PageIndexChanging(ByVal sender As Object, ByVal e As GridViewPageEventArgs)
TaskGridView.PageIndex = e.NewPageIndex
'Bind data to the GridView control.
BindData()
End Sub
Protected Sub TaskGridView_RowEditing(ByVal sender As Object, ByVal e As GridViewEditEventArgs)
'Set the edit index.
TaskGridView.EditIndex = e.NewEditIndex
'Bind data to the GridView control.
BindData()
End Sub
Protected Sub TaskGridView_RowCancelingEdit()
'Reset the edit index.
TaskGridView.EditIndex = -1
'Bind data to the GridView control.
BindData()
End Sub
Protected Sub TaskGridView_RowUpdating(ByVal sender As Object, ByVal e As GridViewUpdateEventArgs)
'Retrieve the table from the session object.
Dim dt = CType(Session("TaskTable"), DataTable)
'Update the values.
Dim row = TaskGridView.Rows(e.RowIndex)
dt.Rows(row.DataItemIndex)("Id") = (CType((row.Cells(1).Controls(0)), TextBox)).Text
dt.Rows(row.DataItemIndex)("Description") = (CType((row.Cells(2).Controls(0)), TextBox)).Text
dt.Rows(row.DataItemIndex)("IsComplete") = (CType((row.Cells(3).Controls(0)), CheckBox)).Checked
'Reset the edit index.
TaskGridView.EditIndex = -1
'Bind data to the GridView control.
BindData()
End Sub
Private Sub BindData()
TaskGridView.DataSource = Session("TaskTable")
TaskGridView.DataBind()
End Sub
</script>

Answer 3

I have a access connection with textbox as data feeder to database change it to SQL if u want. The code is:
Imports System
Imports System.Data
Imports System.Data.OleDb
Public Class Form2
Dim conaccess As New OleDbConnection
Dim conreader As OleDbDataReader
Dim concmd As New OleDbCommand
Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
DataGridView1.EditMode = False
conaccess.ConnectionString = "Provider=Microsoft.jet.oledb.4.0;data source=d:\vijay.mdb"
conaccess.Open()
loadGrid()
End Sub
Private Sub loadGrid()
Dim access As String
access = "select * from vijay"
Dim DataTab As New DataTable
Dim DataAdap As New OleDbDataAdapter(access, conaccess)
DataAdap.Fill(DataTab)
DataGridView1.DataSource = DataTab
End Sub
Private Sub new_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles new_btn.Click
Dim no As String
no = "select Max(ID) from vijay"
Dim concmd As New OleDbCommand(no, conaccess)
conreader = concmd.ExecuteReader
If (conreader.Read) Then
If (IsDBNull(conreader(0))) Then
id_txt.Text = "1"
Else
id_txt.Text = conreader(0) + 1
End If
name_txt.Clear()
branch_txt.Clear()
age_txt.Clear()
class_txt.Clear()
gen_txt.Clear()
End If
End Sub
Private Sub DataGridView1_CellClick(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellClick
Dim i As Integer
i = DataGridView1.CurrentRow.Index
Try
id_txt.Text = DataGridView1.Item(0, i).Value
name_txt.Text = DataGridView1.Item(1, i).Value
class_txt.Text = DataGridView1.Item(2, i).Value
gen_txt.Text = DataGridView1.Item(3, i).Value
branch_txt.Text = DataGridView1.Item(4, i).Value
age_txt.Text = DataGridView1.Item(5, i).Value
Catch ex As Exception
End Try
End Sub
Private Sub del_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles del_btn.Click
Dim delcmd As New OleDbCommand("delete from vijay where id=" & id_txt.Text & " ", conaccess)
delcmd.ExecuteNonQuery()
MsgBox("Record is deleted")
loadGrid()
id_txt.Clear()
name_txt.Clear()
branch_txt.Clear()
age_txt.Clear()
class_txt.Clear()
gen_txt.Clear()
End Sub
Private Sub save_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles save_btn.Click
Dim access As String = String.Format("INSERT INTO vijay (Name,Class,Branch,Gender,Age) VALUES('{0}','{1}','{2}','{3}','{4}')", name_txt.Text, class_txt.Text, branch_txt.Text, gen_txt.Text, age_txt.Text)
concmd.Connection = conaccess
concmd.CommandText = access
concmd.ExecuteNonQuery()
MsgBox("Record Successfully Saved")
loadGrid()
id_txt.Clear()
name_txt.Clear()
branch_txt.Clear()
age_txt.Clear()
class_txt.Clear()
gen_txt.Clear()
End Sub
Private Sub up_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles up_btn.Click
Dim access As String
access = "UPDATE vijay SET Name = '" & name_txt.Text & "', Age = '" & age_txt.Text & "', Gender ='" & gen_txt.Text & "' , Branch ='" & branch_txt.Text & "' , Class = '" & class_txt.Text & "' where id=" & id_txt.Text & ""
Dim cmd As New OleDbCommand(access, conaccess)
cmd.ExecuteNonQuery()
loadGrid()
id_txt.Clear()
name_txt.Clear()
branch_txt.Clear()
age_txt.Clear()
class_txt.Clear()
gen_txt.Clear()
End Sub
End Class

Answer 4

Use looping and parameter (to handle sql injection):
con.Open() 'Open connection to database
'Looping throung dgv
For i As Integer = 0 To dgvEmpDetail.Rows.Count - 1
If IsDBNull(dgvEmpDetail.Rows(i).Cells("Emp_ID").Value) Then Exit For
Dim cmd As New SqlCommand("Update EmployeeDetail Set [Salary] = ?, [Experience]=?, [Skills]=? WHERE [Emp_ID] =?", con)
With cmd.Parameters
.AddWithValue("#Salary", dgvEmpDetail.Rows(i).Cells("Salary").Value )
.AddWithValue("#Experience", dgvEmpDetail.Rows(i).Cells("Experience").Value )
.AddWithValue("#Skills", dgvEmpDetail.Rows(i).Cells("Skills").Value )
.AddWithValue("#Emp_ID", dgvEmpDetail.Rows(i).Cells("Emp_ID").Value )
End With
cmd.ExecuteNonQuery()
Next i
con.Close() 'Close connection with Database