C# Form.show() 错误 System.InvalidOperationException

Question

I am trying fill three ComboBox with a Class list, but it is giving an error:

An unhandled exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll

"System.InvalidOperationException: This operation cannot be performed while an auto-filled column is being resized"

This error happens occasionally, but never fails to happen.

And this point to form.Show();

Code:

 Catalogo form = new Catalogo();
 form.Show();

And this is the form of code:

private void btSair_Click(object sender, EventArgs e)
{
    DialogResult var;
    var = MessageBox.Show("Deseja fechar esta janela ? ", "", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
    if (var == DialogResult.Yes)
    {
        GC.Collect(GC.MaxGeneration, GCCollectionMode.Forced);
        this.Close();   
    }
}

private void Catalogo_Load(object sender, EventArgs e)
{
    cliente = new KEYSERVICEClient();
    List<Catalogo> asdf = new List<Catalogo>();

    var listar = cliente.FillCombosCatalogo(Global.Id_empresa);

    for (int i = 0; i < listar.Count; i++)
    {
        cbFabricante.Items.Add(listar[i].fabricante);
        cbModelo.Items.Add(listar[i].modelo);
        cbNumera.Items.Add(listar[i].numeracao);
    }
}

FillComboCatalogo method:

public List<CatalogoItens> FillCombosCatalogo(int id_empresa)
{
    SqlDataReader objReader;
    SqlCommand objcmd = null;

    vsql = "SELECT [ID_EMPRESA], [MODELO], [FABRICANTE],[NUMERACAO] As Identificador,[MODELO],[FABRICANTE], [NUMERACAO] FROM PRODUTOS_CHAVES WHERE @ID_EMPRESA = ID_EMPRESA";

    List<CatalogoItens> catag = new List<CatalogoItens>();

    if (this.Conectar())
    {
        try
        {
            objcmd = new SqlCommand(vsql, objCon);

            objcmd.Parameters.Add(new SqlParameter("@ID_EMPRESA", id_empresa));

            objReader = objcmd.ExecuteReader();

            while (objReader.Read())
            {
                CatalogoItens catalogo = new CatalogoItens()
                {
                    modelo = (objReader.GetString(1)),
                    fabricante = (objReader.GetString(2)),
                    numeracao = (objReader.GetString(3))
                };
                catag.Add(catalogo);
            }
                return catag;
        }
        catch
        {

        }
        finally
        {
            this.Desconectar();
        }
    }
    return null;
}

Answer 1

If you want change combobox items, and add lots of them (in a loop) always use Suspend/ResumeLayout.

Eg.:

cbFabricante.SuspendLayout();
cbModelo.SuspendLayout();
cbNumera.SuspendLayout();
for (int i = 0; i < listar.Count; i++)
{
    cbFabricante.Items.Add(listar[i].fabricante);
    cbModelo.Items.Add(listar[i].modelo);
    cbNumera.Items.Add(listar[i].numeracao);
}
cbFabricante.ResumeLayout();
cbModelo.ResumeLayout();
cbNumera.ResumeLayout();

If you don't do that, system will redraw combobox every time you add an item, instead of redraw it once - after adding all items.

It could be the cause of the exception. It this will not help, provide us with parameters you set in those comboboxes