.NET (Core and Framework)

...
cmd.Parameters.AddWithValue("@DateTime", Form1.DateTimePicker1.Value)
cmd.ExecuteNonQuery()

cmd1.CommandText = "select * from StudentInfo where Code = @Code"
cmd1.Parameters.AddWithValue("@Code", Form1.txtCode.Text)

Using con As New SqlConnection(strconnection)
    Using cmd As SqlCommand = con.CreateCommand()
        ...
    End Using
End Using

SAVE BUTTON
-------------

Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
    Try
        Dim strconnection As String = "Data Source=ELIANE-VAIO\SQLEXPRESS;Initial Catalog=SchoolDB;Integrated Security=True;"
        Dim _cn As SqlConnection = New SqlConnection(strconnection)
        Dim cmd As New SqlCommand
        _cn.Open()
        cmd.CommandText = "INSERT INTO StudentInfo([Code], [Full-Name], [Position], [Title], [Phone-Number], [Address], [Date-Time]) VALUES (<a href="/Members/code">@Code</a>, <a href="/Members/Name">@Name</a>, <a href="/Members/position">@Position</a>, <a href="/Members/title">@Title</a>, @PhoneNumber, <a href="/Members/address">@Address</a>, <a href="/Members/datetime">@DateTime</a>);"
        cmd.Connection = _cn
        cmd.Parameters.AddWithValue("<a href="/Members/code">@Code</a>", Val(Me.t1.Text))
        cmd.Parameters.AddWithValue("<a href="/Members/Name">@Name</a>", Me.t2.Text)
        cmd.Parameters.AddWithValue("<a href="/Members/position">@Position</a>", Me.c1.Text)
        cmd.Parameters.AddWithValue("<a href="/Members/title">@Title</a>", Me.c2.Text)
        cmd.Parameters.AddWithValue("@PhoneNumber", Me.t5.Text)
        cmd.Parameters.AddWithValue("<a href="/Members/address">@Address</a>", Me.t6.Text)
        cmd.Parameters.AddWithValue("<a href="/Members/datetime">@DateTime</a>", Me.t7.Value)
        cmd.ExecuteNonQuery()
        _cn.Close()
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try
End Sub

Private Sub btnRemove_Click(sender As Object, e As EventArgs) Handles btnRemove.Click
        Me.StudentInfoBindingSource.RemoveCurrent()

        Dim con As New SqlConnection
        Dim cmd As New SqlCommand
        Try
            Dim strconnection As String = "Data Source=ELIANE-VAIO\SQLEXPRESS;Initial Catalog=SchoolDB;Integrated Security=True;"
            Dim _cn As SqlConnection = New SqlConnection(strconnection)
            _cn.Open()
            cmd.Connection = _cn
            cmd.CommandText = "Delete From studentInfo where code= " & Val(t1.Text)
            'cmd.Parameters.Add(New SqlParameter("<a href="/Members/code">@code</a>", 99))

            If MessageBox.Show("Do you really want to Delete this Record?", "Delete", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) = DialogResult.No Then
                MsgBox("Operation Cancelled")
                Exit Sub
            Else
                cmd.ExecuteNonQuery()
            End If
        Catch ex As Exception
            MessageBox.Show("Error while deleting record on table..." & ex.Message, "Delete Records")
        Finally
            con.Close()
        End Try
    End Sub

cmd.CommandText = "delete from StudentInfo where Code = @Code"
cmd.Parameters.AddWithValue("@Code", t1.Text)

Member 10388494 wrote:

Here is one of them.

Member 10388494 wrote:

Violation of PRIMARY KEY constraint 'PK_StudentInfo'. Cannot insert duplicate key in object 'dbo.StudentInfo'.

Member 10388494 wrote:

<layer>but i am sure 100% that there is no record that have the same code.

Bastard Programmer from Hell
If you can't read my code, try converting it here[^]

enum Gender{
   Male,
   Female
};

dim Male as boolean = RDMale.checked

SateeshVankayala wrote:

urgent please