Windows窗体中的布局困难

Question

I'm programming an application in C# with Windows Forms. It is a form with a menu, a tabbed pane, a grid and a status bar. I'd like the controls to show up correctly even when resizing the window. If I add the controls to the form without using any layout panel, the menu bar shows up on top of the tabs (see Figure 1). On the other hand, if I use a FlowLayoutPanel in order to add the components from top to bottom, the controls don't fill the available space (see Figure 2).

EDIT: I couldn't solve it using a TableLayoutPanel. The vertical space isn't filled either. See Figure 3.

What may be the problem? What is the usual way to work with Layouts in Windows Forms? Thank you in advance.

The code is the following:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using AGAPconsole;

namespace AGAP
{
public partial class MainForm : Form
{

    private String user;
    private ClassDatabase db;

    private TableLayoutPanel mainPanel;
    private TabControl mainTabControl;
    private TabPage mainTabPage;

    // Grid de actuaciones
    private DataGridView actuacionesGrid;
    private ContextMenuStrip actuacionesContextMenuStrip;
    private ToolStripMenuItem verTramitesMenuItem;
    private ToolStripMenuItem verEncargosMenuItem;
    private ToolStripMenuItem verTrabajosMenuItem;
    private ToolStripMenuItem verDatosObraMenuItem;

    // Barra de estado
    private StatusStrip mainStatusStrip;
    private ToolStripStatusLabel mainStatusLabel;

    // Menu
    private MenuStrip mainMenuStrip;
    private ToolStripMenuItem archivoMenuItem;
    private ToolStripMenuItem salirMenuItem;
    private ToolStripMenuItem abrirMenuItem;

    // Importacion
    private OpenFileDialog openFileDialog;

    // Users
    public static String USER_CONSULTA_CORUNA = "Delegación C (R)";
    public static String USER_EDICION_CORUNA = "Delegación C (RW)";
    public static String USER_CONSULTA_OURENSE = "Delegación OU-LU (R)";
    public static String USER_EDICION_OURENSE = "Delegación OU-LU (RW)";
    public static String USER_CONSULTA_PONTEVEDRA = "Delegación PO (R)";
    public static String USER_EDICION_PONTEVEDRA = "Delegación PO (RW)";
    public static String USER_IMPORTACION = "Importación";
    public static String USER_ZONA = "Zona";

    public static String[] USERS = { USER_ZONA, USER_CONSULTA_CORUNA, 
                                       USER_EDICION_CORUNA, USER_CONSULTA_OURENSE, 
                                       USER_EDICION_OURENSE, USER_CONSULTA_PONTEVEDRA, 
                                       USER_EDICION_PONTEVEDRA, USER_IMPORTACION };

    public MainForm(String user)
    {
        this.user = user;
        db = new ClassDatabase();
        //InitializeComponent();
        //this.AutoScaleDimensions = new SizeF(6F, 13F);
        this.AutoScaleMode = AutoScaleMode.Font;
        this.ClientSize = new Size(984, 762);
        this.Name = "MainForm";
        //this.StartPosition = FormStartPosition.CenterScreen;
        this.Text = "AGAP";
        this.WindowState = FormWindowState.Maximized;
        this.BackColor = SystemColors.Window;

        this.Controls.Add(CreateMainPanel());

        // Menu
        mainPanel.Controls.Add(CreateMainMenuStrip());

        // Contenido dependiendo del usuario

        // El menu tendra Archivo -> Salir a no ser que sea el usuario de importacion,
        // que tendra mas cosas.
        if (!user.Equals(USER_IMPORTACION))
        {
            //CreateArchivoSalir();
            CreateSalir();
        }

        if (user.Equals(USER_ZONA))
        {
            this.Text = "AGAP Visualización de datos";
            InitVisualizacion();
        }

        if (user.Equals(USER_IMPORTACION))
        {
            this.Text = "AGAP Importación de datos";
            InitImportacion();
        }

        // Barra de estado
        mainPanel.Controls.Add(CreateMainStatusStrip());
        this.mainStatusLabel.Text = "Autenticado como " + user;
    }

    private void InitImportacion()
    {
        CreateOpenFileDialog();
        // this.Controls.Add(CreateMainPanel());
        // mainPanel.Controls.Add(CreateMainMenuStrip());
        mainMenuStrip.Items.Add(CreateArchivoMenuItem());
        archivoMenuItem.DropDownItems.Add(CreateAbrirMenuItem());
        archivoMenuItem.DropDownItems.Add("-");
        archivoMenuItem.DropDownItems.Add(CreateSalirMenuItem());
    }

    private void InitVisualizacion()
    {
        // this.Controls.Add(CreateMainPanel());
        mainPanel.Controls.Add(CreateMainTabControl());
        mainTabPage.Controls.Add(CreateActuacionesGrid());
        mainTabPage.Text = "Actuaciones";
        actuacionesGrid.Name = "actuacionesGrid";
    }

    private OpenFileDialog CreateOpenFileDialog()
    {
        if (openFileDialog == null)
        {
            openFileDialog = new OpenFileDialog();
            openFileDialog.AutoUpgradeEnabled = true;
            openFileDialog.Filter = "Archivos CSV, Excel (*.csv, *.xls, *.xlsx)|*.csv;*.xls;*.xlsx|Todos los archivos (*.*)|*.*";
            openFileDialog.ValidateNames = true;
        }
        return openFileDialog;
    }

    private ToolStripMenuItem CreateAbrirMenuItem()
    {
        if (abrirMenuItem == null)
        {
            abrirMenuItem = new ToolStripMenuItem();
            abrirMenuItem.Name = "abrirMenuItem";
            abrirMenuItem.Text = "&Abrir...";
            abrirMenuItem.Click += new EventHandler(abrirMenuItem_Click);
            abrirMenuItem.ShortcutKeys = ((Keys)((Keys.Control | Keys.O)));
        }
        return abrirMenuItem;
    }

    private void abrirMenuItem_Click(object sender, EventArgs e)
    {
        DialogResult result = openFileDialog.ShowDialog();
        if (result == DialogResult.OK)
        {
            bool ret = false;
            string file = openFileDialog.FileName;
            if (file.EndsWith(".csv"))
            {
                ret = CSVparser.parseCSV(file);
            }
            else
            {
                // Parse Excel file
            }
            string messageBoxText;
            MessageBoxIcon icon;
            if (ret)
            {
                messageBoxText = "Importación finalizada";
                icon = MessageBoxIcon.Information;
            }
            else
            {
                messageBoxText = "La importación ha fracasado. Se ha producido un error.";
                icon = MessageBoxIcon.Warning;
            }
            string caption = "AGAP Importación de datos";
            MessageBoxButtons buttons = MessageBoxButtons.OK;
            MessageBox.Show(messageBoxText, caption, buttons, icon);
        }
    }

    private void CreateSalir()
    {
        mainMenuStrip.Items.Add(CreateSalirMenuItem());
    }

    private void CreateArchivoSalir()
    {
        mainMenuStrip.Items.Add(CreateArchivoMenuItem());
        archivoMenuItem.DropDownItems.Add(CreateSalirMenuItem());
    }

    #region Creacion de controles
    private MenuStrip CreateMainMenuStrip()
    {
        if (mainMenuStrip == null)
        {
            mainMenuStrip = new MenuStrip();
            mainMenuStrip.Name = "mainMenuStrip";
            mainMenuStrip.Anchor = AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right;
        }
        return mainMenuStrip;
    }

    private ToolStripMenuItem CreateArchivoMenuItem()
    {
        if (archivoMenuItem == null)
        {
            archivoMenuItem = new ToolStripMenuItem();
            archivoMenuItem.Name = "archivoToolStripMenuItem";
            archivoMenuItem.Text = "&Archivo";

        }
        return archivoMenuItem;
    }

    private ToolStripMenuItem CreateSalirMenuItem()
    {
        if (salirMenuItem == null)
        {
            salirMenuItem = new ToolStripMenuItem();
            salirMenuItem.Name = "salirToolStripMenuItem";
            salirMenuItem.Text = "&Salir...";
            salirMenuItem.Click += new EventHandler(salirMenuItem_Click);
            salirMenuItem.ShortcutKeys = ((Keys)((Keys.Control | Keys.Q)));
        }
        return salirMenuItem;
    }

    private StatusStrip CreateMainStatusStrip()
    {
        if (mainStatusStrip == null)
        {
            mainStatusStrip = new StatusStrip();
            mainStatusStrip.Name = "mainStatusStrip";
            mainStatusStrip.BackColor = SystemColors.Window;
            mainStatusStrip.Anchor = AnchorStyles.Bottom | AnchorStyles.Left | AnchorStyles.Right;
            mainStatusStrip.Items.Add(CreateMainStatusLabel());
        }
        return mainStatusStrip;
    }

    private ToolStripStatusLabel CreateMainStatusLabel()
    {
        if (mainStatusLabel == null)
        {
            mainStatusLabel = new ToolStripStatusLabel();
            mainStatusLabel.Name = "mainStatusLabel";
            mainStatusLabel.BackColor = SystemColors.Window;
        }
        return mainStatusLabel;
    }
    private TableLayoutPanel CreateMainPanel()
    {
        if (mainPanel == null)
        {
            mainPanel = new TableLayoutPanel();
            mainPanel.Name = "mainPanel";
            mainPanel.Dock = DockStyle.Fill;
            //mainPanel.FlowDirection = FlowDirection.TopDown;
            mainPanel.Size = new Size(1280, 1024);
            mainPanel.ColumnCount = 1;
            mainPanel.RowCount = 3;
        }
        return mainPanel;
    }

    private TabControl CreateMainTabControl()
    {
        if (mainTabControl == null)
        {
            mainTabControl = new TabControl();
            mainTabControl.Controls.Add(CreateMainTabPage());
            //mainTabControl.Location = new Point(0, 0);
            mainTabControl.Name = "mainTabControl";
            mainTabControl.SelectedIndex = 0;
            //this.mainTabControl.Size = new System.Drawing.Size(745, 559);
            //mainTabControl.TabIndex = 0;
            //mainTabControl.Size = new Size(1280, 1024);
            mainTabControl.Dock = DockStyle.Fill;
            //mainTabControl.Dock = DockStyle.Bottom | DockStyle.Top | DockStyle.Left;
            //mainTabControl.Anchor = AnchorStyles.Bottom | AnchorStyles.Top | AnchorStyles.Left | AnchorStyles.Right ;
            mainTabControl.MouseClick += new MouseEventHandler(mainTabControl_MouseClick);
        }
        return mainTabControl;
    }

    private void mainTabControl_MouseClick(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Right)
        {
            ContextMenuStrip cms = CreateMainTabControlContextMenuStrip();
            cms.Show(mainTabControl, e.Location);
        }
        if (e.Button == MouseButtons.Middle)
        {
            if (mainTabControl.SelectedIndex != 0)
            {
                mainTabControl.TabPages.Remove(mainTabControl.SelectedTab);
            }
        }
    }

    private ContextMenuStrip CreateMainTabControlContextMenuStrip()
    {
        ContextMenuStrip cms = new ContextMenuStrip();
        cms.Items.AddRange(new ToolStripMenuItem[] { CreateCloseTabMenuItem() });
        return cms;
    }

    private ToolStripMenuItem CreateCloseTabMenuItem()
    {
        var closeTabMenuItem = new ToolStripMenuItem();
        closeTabMenuItem.Text = "&Cerrar pestaña";
        closeTabMenuItem.Click += new EventHandler(closeTabMenuItem_Click);
        //closeTabMenuItem.ShortcutKeys = ((Keys)((Keys.Control | Keys.F4)));
        return closeTabMenuItem;
    }

    private void closeTabMenuItem_Click(object sender, EventArgs e)
    {
        if (mainTabControl.SelectedIndex != 0)
        {
            mainTabControl.TabPages.Remove(mainTabControl.SelectedTab);
        }
    }

    private TabPage CreateTabPage()
    {
        var tabPage = new TabPage();
        //tabPage.Location = new Point(4, 22);
        //tabPage.Padding = new Padding(3);
        //tabPage.UseVisualStyleBackColor = true;
        return tabPage;
    }

    private TabPage CreateMainTabPage()
    {
        if (mainTabPage == null)
        {
            mainTabPage = CreateTabPage();
            mainTabPage.Name = "mainTabPage";
            mainTabPage.Text = "Actuaciones";
            //mainTabPage.TabIndex = 0;
        }
        return mainTabPage;
    }

    private DataGridView CreateGrid()
    {
        DataGridView grid = new DataGridView();
        // Propiedades fijas
        grid.AllowUserToOrderColumns = true;
        grid.RowHeadersVisible = false;
        grid.StandardTab = false;
        grid.ReadOnly = true;
        grid.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
        grid.MultiSelect = false;
        grid.ScrollBars = ScrollBars.Both;
        grid.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.DisplayedCells;
        grid.BackgroundColor = SystemColors.Window;

        // Propiedades dudosas
        //grid.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
        grid.Dock = DockStyle.Fill;
        //grid.Location = new Point(0, 0);
        //grid.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders;
        grid.TabIndex = 0;
        //grid.Size = new Size(1280, 1024);
        //grid.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;
        //grid.AutoSize = true;

        //grid.PerformLayout();

        return grid;
    }

    private DataGridView CreateActuacionesGrid()
    {
        if (actuacionesGrid == null)
        {
            actuacionesGrid = CreateGrid();
            actuacionesGrid.MouseDown += new MouseEventHandler(actuacionesGrid_MouseDown);
            actuacionesGrid.DataSource = ComunicacionBD.SelectActuaciones(db).Tables[0].DefaultView;
            actuacionesGrid.ContextMenuStrip = CreateActuacionesContextMenuStrip();
        }
        return actuacionesGrid;
    }

    private ContextMenuStrip CreateActuacionesContextMenuStrip()
    {
        if (actuacionesContextMenuStrip == null)
        {
            actuacionesContextMenuStrip = new ContextMenuStrip();
            actuacionesContextMenuStrip.Name = "actuacionesContextMenuStrip";
            actuacionesContextMenuStrip.Items.AddRange(new ToolStripMenuItem[] { CreateVerTramitesMenuItem(),
                CreateVerEncargosMenuItem(), CreateVerTrabajosMenuItem(), CreateVerDatosObraMenuItem()});
        }
        return actuacionesContextMenuStrip;
    }

    private ToolStripMenuItem CreateVerDatosObraMenuItem()
    {
        if (verDatosObraMenuItem == null)
        {
            verDatosObraMenuItem = new ToolStripMenuItem();
            verDatosObraMenuItem.Name = "verDatosObraMenuItem";
            verDatosObraMenuItem.Text = "Ver &datos de obra";
            verDatosObraMenuItem.Click += new EventHandler(verDatosObraMenuItem_Click);
            verDatosObraMenuItem.ShortcutKeys = ((Keys)((Keys.Control | Keys.D)));
        }
        return verDatosObraMenuItem;
    }

    private ToolStripMenuItem CreateVerTramitesMenuItem()
    {
        if (verTramitesMenuItem == null)
        {
            verTramitesMenuItem = new ToolStripMenuItem();
            verTramitesMenuItem.Name = "verTramitesMenuItem";
            verTramitesMenuItem.Text = "Ver &trámites";
            verTramitesMenuItem.Click += new EventHandler(verTramitesMenuItem_Click);
            verTramitesMenuItem.ShortcutKeys = ((Keys)((Keys.Control | Keys.T)));
        }
        return verTramitesMenuItem;
    }

    private ToolStripMenuItem CreateVerEncargosMenuItem()
    {
        if (verEncargosMenuItem == null)
        {
            verEncargosMenuItem = new ToolStripMenuItem();
            verEncargosMenuItem.Name = "verEncargosMenuItem";
            verEncargosMenuItem.Text = "Ver &encargos";
            verEncargosMenuItem.Click += new EventHandler(verEncargosMenuItem_Click);
            verEncargosMenuItem.ShortcutKeys = ((Keys)((Keys.Control | Keys.E)));
        }
        return verEncargosMenuItem;
    }

    private ToolStripMenuItem CreateVerTrabajosMenuItem()
    {
        if (verTrabajosMenuItem == null)
        {
            verTrabajosMenuItem = new ToolStripMenuItem();
            verTrabajosMenuItem.Name = "verTrabajosMenuItem";
            verTrabajosMenuItem.Text = "Ver t&rabajos";
            verTrabajosMenuItem.Click += new EventHandler(verTrabajosMenuItem_Click);
            verTrabajosMenuItem.ShortcutKeys = ((Keys)((Keys.Control | Keys.W)));
        }
        return verTrabajosMenuItem;
    }

    #endregion

    #region Event Handlers
    private void actuacionesGrid_MouseDown(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Right)
        {
            var hti = actuacionesGrid.HitTest(e.X, e.Y);
            actuacionesGrid.ClearSelection();
            actuacionesGrid.Rows[hti.RowIndex].Selected = true;
        }
    }

    private void verTramitesMenuItem_Click(object sender, EventArgs e)
    {
        // Coger la actuacion seleccionada.
        //Actuacion act = (Actuacion) actuacionesGrid.CurrentRow.DataBoundItem;
        string obraid = actuacionesGrid.CurrentRow.Cells["ObraId"].Value.ToString();

        // Crear la pestaña.
        var tabPage = CreateTabPage();
        tabPage.Name = "tramitesTabPage" + obraid;
        tabPage.Text = "Trámites actuación " + obraid;
        mainTabControl.TabPages.Add(tabPage);
        mainTabControl.SelectedTab = tabPage;

        // Crear el FlowLayoutPanel
        //var panel = new FlowLayoutPanel();
        //tabPage.Controls.Add(panel);

        // Crear el panel con las labels de la actuacion
        //panel.Controls.Add(CreateActuacionPanel(act));

        // Crear la tabla
        var grid = CreateTramitesGrid();
        grid.DataSource = ComunicacionBD.SelectTramites(db, obraid).Tables[0].DefaultView;
        tabPage.Controls.Add(grid);
    }

    private void verDatosObraMenuItem_Click(object sender, EventArgs e)
    {
        // Coger la actuacion seleccionada.
        //Actuacion act = (Actuacion) actuacionesGrid.CurrentRow.DataBoundItem;
        string obraid = actuacionesGrid.CurrentRow.Cells["ObraId"].Value.ToString();

        // Crear la pestaña.
        var tabPage = CreateTabPage();
        tabPage.Name = "datosObraTabPage" + obraid;
        tabPage.Text = "Datos de obra " + obraid;
        mainTabControl.TabPages.Add(tabPage);
        mainTabControl.SelectedTab = tabPage;

        // Crear el FlowLayoutPanel
        //var panel = new FlowLayoutPanel();
        //tabPage.Controls.Add(panel);

        // Crear el panel con las labels de la actuacion
        //panel.Controls.Add(CreateActuacionPanel(act));

        // Crear la tabla
        var grid = CreateTramitesGrid();
        grid.DataSource = ComunicacionBD.SelectDatosObra(db, obraid).Tables[0].DefaultView;
        tabPage.Controls.Add(grid);
    }


    private Panel CreateActuacionPanel(Actuacion act)
    {
        var actuacionPanel = new FlowLayoutPanel();
        actuacionPanel.FlowDirection = FlowDirection.LeftToRight;

        var actuacionLabel = new Label();
        actuacionLabel.Text = "Actuación: " + act.ActuacionId;

        var descLabel = new Label();
        descLabel.Text = "Descripción: " + act.Descripcion;

        actuacionPanel.Controls.Add(actuacionLabel);
        actuacionPanel.Controls.Add(descLabel);
        return actuacionPanel;
    }

    private DataGridView CreateTramitesGrid()
    {
        var grid = CreateGrid();
        return grid;
    }

    private DataGridView CreateTrabajosGrid()
    {
        var grid = CreateGrid();
        return grid;
    }

    private void verEncargosMenuItem_Click(object sender, EventArgs e)
    {
        // Coger la actuacion seleccionada.
        //Actuacion act = (Actuacion) actuacionesGrid.CurrentRow.DataBoundItem;
        string obraid = actuacionesGrid.CurrentRow.Cells["ObraId"].Value.ToString();

        // Crear la pestaña.
        var tabPage = CreateTabPage();
        tabPage.Name = "encargosTabPage" + obraid;
        tabPage.Text = "Encargos actuación " + obraid;
        mainTabControl.TabPages.Add(tabPage);
        mainTabControl.SelectedTab = tabPage;

        // Crear el FlowLayoutPanel
        //var panel = new FlowLayoutPanel();
        //tabPage.Controls.Add(panel);

        // Crear el panel con las labels de la actuacion
        //panel.Controls.Add(CreateActuacionPanel(act));

        // Crear la tabla
        var grid = CreateTrabajosGrid();
        grid.DataSource = ComunicacionBD.SelectEncargos(db, obraid).Tables[0].DefaultView;
        tabPage.Controls.Add(grid);
    }

    private void verTrabajosMenuItem_Click(object sender, EventArgs e)
    {
        // Coger la actuacion seleccionada.
        //Actuacion act = (Actuacion) actuacionesGrid.CurrentRow.DataBoundItem;
        string obraid = actuacionesGrid.CurrentRow.Cells["ObraId"].Value.ToString();

        // Crear la pestaña.
        var tabPage = CreateTabPage();
        tabPage.Name = "trabajosTabPage" + obraid;
        tabPage.Text = "Trabajos actuación " + obraid;
        mainTabControl.TabPages.Add(tabPage);
        mainTabControl.SelectedTab = tabPage;

        // Crear el FlowLayoutPanel
        //var panel = new FlowLayoutPanel();
        //tabPage.Controls.Add(panel);

        // Crear el panel con las labels de la actuacion
        //panel.Controls.Add(CreateActuacionPanel(act));

        // Crear la tabla
        var grid = CreateTrabajosGrid();
        grid.DataSource = ComunicacionBD.SelectTrabajos(db, obraid).Tables[0].DefaultView;
        tabPage.Controls.Add(grid);
    }

    private void salirMenuItem_Click(object sender, EventArgs e)
    {
        Close();
    }
    #endregion

    // Por culpa de tener un Form de Login antes, hay que hacer este metodo asi.
    // Seguramente hay formas mejores de hacerlo, pero esto funciona.
    protected override void OnFormClosing(FormClosingEventArgs e)
    {
        base.OnFormClosing(e);

        if (e.CloseReason == CloseReason.WindowsShutDown)
        {
            return;
        }

        switch (MessageBox.Show(this, "¿Salir ahora?", "Salir", MessageBoxButtons.YesNo))
        {
            case DialogResult.Yes:
                break;
            default:
                e.Cancel = true;
                break;
        }
        if (!e.Cancel)
        {
            Environment.Exit(0);
        }
    }
}

}

Answer 1

You have to use TableLayoutPanel instead of FlowLayoutPanel .

FlowLayoutPanel is used to form a stack of controls, one after another and solving wrapping. TableLayoutPanel is a table with all sort of cell manipulations: extending to more cells vertically/horizontally, sizing, proportioning, etc.

For your task you will need TableLayoutPanel :

• Only one column;
• 3 rows: for menu (autosize), for DataGridView (inside tabbed pane I guess?) (100%) and for status bar (autosize).

Then set TableLayoutPanel docking to Fill and it should be pretty much about it.

A tip: make sure you put controls inside cells before setting row to AutoSize .

Point here is what TableLayoutPanel can assign specified percentage (in our case 100% or any other value will do, as there is only 1 row requesting percentage of size) and will increase/decrease cell size if size of panel is changed. Then you can use cell to dock/anchor control inside the cell in a way you like. For this see @Hassan Nisar answer, it will not solve your issue though in its current form, despite it was already upvoted, perhaps as being useful ;-).

Answer 2

You have to set Anchor property of FlowLayoutPanel.

By using this property you can set the edges of the container to which a control is bound and determines how a control is resized with its parent.

For Anchoring and Docking child controls :

Here is MSDN example on How to: Anchor and Dock Child Controls in a FlowLayoutPanel Control .

UPDATE :

This is important note on MSDN regarding FlowLayoutPanel :

General rule for anchoring and docking in the FlowLayoutPanel control: for vertical flow directions, the FlowLayoutPanel control calculates the width of an implied column from the widest child control in the column. All other controls in this column with Anchor or Dock properties are aligned or stretched to fit this implied column. The behavior works in a similar way for horizontal flow directions. The FlowLayoutPanel control calculates the height of an implied row from the tallest child control in the row, and all docked or anchored child controls in this row are aligned or sized to fit the implied row.

For vertical flow direction :
Supply Size of widest child control. (For example control can be datagridview1 in your case.

For horizontal flow direction :
Supply Size of tallest child control.