Ytukyg

In the following code:

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using System.Data.SQLite;

using System.Diagnostics;



namespace WindowsFormsApplication1

{

    public partial class List : Form

    {

        public List()

        {

            InitializeComponent();

        }



        private void List_Load(object sender, EventArgs e)

        {

            comboBox1.SelectedIndex = 1;

        }



        private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)

        {

            var cmd = new SQLiteCommand("select * from students", DB.Connection);

            var ad = new SQLiteDataAdapter(cmd);

            var dt = new DataTable();

            ad.Fill(dt);

            listBox1.DataSource = dt;

            listBox1.DisplayMember = "name";

        }



        private void btnAdd_Click(object sender, EventArgs e)

        {

            Debug.Assert(listBox1.DataSource is DataTable);

            var dt = listBox1.DataSource as DataTable;

            dt.Rows.Add();

            btnEdit.Enabled = btnRemove.Enabled = dt.Rows.Count != 0;

        }



        private void btnEdit_Click(object sender, EventArgs e)

        {

            Debug.Assert(listBox1.SelectedItem is DataRowView);

            new StudentsForm2(listBox1.SelectedItem as DataRowView).ShowDialog(this);

        }



        private void btnRemove_Click(object sender, EventArgs e)

        {

            Debug.Assert(listBox1.DataSource is DataTable);

            var dt = listBox1.DataSource as DataTable;

            dt.Rows.RemoveAt(listBox1.SelectedIndex);

            btnEdit.Enabled = btnRemove.Enabled = dt.Rows.Count != 0;

        }



        private void List_KeyDown(object sender, KeyEventArgs e)

        {

            if (e.KeyCode == Keys.Escape)

            {

                Close();

            }

        }



    }

}

when the table is empty, I get the following exception:

A first chance exception of type 'System.ArgumentOutOfRangeException' occurred in System.Windows.Forms.dll

Additional information: InvalidArgument=Value of '0' is not valid for 'SelectedIndex'.

in method btnAdd_Click when it calls dt.Rows.Add(). comboBox1 holds tables names, but since I only have one table at the moment it's not used unless for comboBox1_SelectedIndexChanged to be called.

Here's the stack trace at the point the exception is thrown:

at System.Environment.GetStackTrace(Exception e, Boolean needFileInfo)
at System.Environment.get_StackTrace()
at System.Windows.Forms.ListBox.set_SelectedIndex(Int32 value)
at System.Windows.Forms.ListControl.DataManager_PositionChanged(Object sender, EventArgs e)
at System.Windows.Forms.CurrencyManager.OnPositionChanged(EventArgs e)
at System.Windows.Forms.CurrencyManager.ChangeRecordState(Int32 newPosition, Boolean validating, Boolean endCurrentEdit, Boolean firePositionChange, Boolean pullData)
at System.Windows.Forms.CurrencyManager.List_ListChanged(Object sender, ListChangedEventArgs e)
at System.Data.DataView.OnListChanged(ListChangedEventArgs e)
at System.Data.DataView.IndexListChanged(Object sender, ListChangedEventArgs e)
at System.Data.DataView.IndexListChangedInternal(ListChangedEventArgs e)
at System.Data.DataViewListener.IndexListChanged(ListChangedEventArgs e)
at System.Data.Index.<>c.b__88_0(DataViewListener listener, ListChangedEventArgs args, Boolean arg2, Boolean arg3)
at System.Data.Listeners1.Notify[T1,T2,T3](T1 arg1, T2 arg2, T3 arg3, Action4 action)
at System.Data.Index.OnListChanged(ListChangedEventArgs e)
at System.Data.Index.OnListChanged(ListChangedType changedType, Int32 index)
at System.Data.Index.InsertRecord(Int32 record, Boolean fireEvent)
at System.Data.Index.ApplyChangeAction(Int32 record, Int32 action, Int32 changeRecord)
at System.Data.Index.RecordStateChanged(Int32 record, DataViewRowState oldState, DataViewRowState newState)
at System.Data.DataTable.RecordStateChanged(Int32 record1, DataViewRowState oldState1, DataViewRowState newState1, Int32 record2, DataViewRowState oldState2, DataViewRowState newState2)
at System.Data.DataTable.SetNewRecordWorker(DataRow row, Int32 proposedRecord, DataRowAction action, Boolean isInMerge, Boolean suppressEnsurePropertyChanged, Int32 position, Boolean fireEvent, Exception& deferredException)
at System.Data.DataTable.InsertRow(DataRow row, Int64 proposedID, Int32 pos, Boolean fireEvent)
at System.Data.DataRowCollection.Add(Object values)
at WindowsFormsApplication1.List.btnAdd_Click(Object sender, EventArgs e) in C:UsershamidiDocumentsVisual Studio 2010Projectsm_rezaeeWindowsFormsApplication1WindowsFormsApplication1List.cs:line 44
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at WindowsFormsApplication1.Program.Main() in C:UsershamidiDocumentsVisual Studio 2010Projectsm_rezaeeWindowsFormsApplication1WindowsFormsApplication1Program.cs:line 18
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()

I couldn't find any clue about why it happens.