Walkthrough: Creating an Unbound Windows Forms DataGridView Control

Artikel
02/04/2013

You may frequently want to display tabular data that does not originate from a database. For example, you may want to show the contents of a two-dimensional array of strings. The DataGridView class provides an easy and highly customizable way to display data without binding to a data source. This walkthrough shows how to populate a DataGridView control and manage the addition and deletion of rows in "unbound" mode. By default, the user can add new rows. To prevent row addition, set the AllowUserToAddRows property is false.

To copy the code in this topic as a single listing, see How to: Create an Unbound Windows Forms DataGridView Control.

Creating the Form

To use an unbound DataGridView control

Create a class that derives from Form and contains the following variable declarations and Main method.

Imports System
Imports System.Drawing
Imports System.Windows.Forms

Public Class Form1
    Inherits System.Windows.Forms.Form

    Private buttonPanel As New Panel
    Private WithEvents songsDataGridView As New DataGridView
    Private WithEvents addNewRowButton As New Button
    Private WithEvents deleteRowButton As New Button


...



    <STAThreadAttribute()> _
    Public Shared Sub Main()
        Application.EnableVisualStyles()
        Application.Run(New Form1())
    End Sub

End Class

using System;
using System.Drawing;
using System.Windows.Forms;

public class Form1 : System.Windows.Forms.Form
{
    private Panel buttonPanel = new Panel();
    private DataGridView songsDataGridView = new DataGridView();
    private Button addNewRowButton = new Button();
    private Button deleteRowButton = new Button();


...



    [STAThreadAttribute()]
    static void Main()
    {
        Application.EnableVisualStyles();
        Application.Run(new Form1());
    }
}

Implement a SetupLayout method in your form's class definition to set up the form's layout.

Private Sub SetupLayout()

    Me.Size = New Size(600, 500)

    With addNewRowButton
        .Text = "Add Row"
        .Location = New Point(10, 10)
    End With

    With deleteRowButton
        .Text = "Delete Row"
        .Location = New Point(100, 10)
    End With

    With buttonPanel
        .Controls.Add(addNewRowButton)
        .Controls.Add(deleteRowButton)
        .Height = 50
        .Dock = DockStyle.Bottom
    End With

    Me.Controls.Add(Me.buttonPanel)

End Sub

private void SetupLayout()
{
    this.Size = new Size(600, 500);

    addNewRowButton.Text = "Add Row";
    addNewRowButton.Location = new Point(10, 10);
    addNewRowButton.Click += new EventHandler(addNewRowButton_Click);

    deleteRowButton.Text = "Delete Row";
    deleteRowButton.Location = new Point(100, 10);
    deleteRowButton.Click += new EventHandler(deleteRowButton_Click);

    buttonPanel.Controls.Add(addNewRowButton);
    buttonPanel.Controls.Add(deleteRowButton);
    buttonPanel.Height = 50;
    buttonPanel.Dock = DockStyle.Bottom;

    this.Controls.Add(this.buttonPanel);
}

Create a SetupDataGridView method to set up the DataGridView columns and properties.

This method first adds the DataGridView control to the form's Controls collection. Next, the number of columns to be displayed is set using the ColumnCount property. The default style for the column headers is set by setting the BackColor, ForeColor, and Font properties of the DataGridViewCellStyle returned by the ColumnHeadersDefaultCellStyle property.

Layout and appearance properties are set, and then the column names are assigned. When this method exits, the DataGridView control is ready to be populated.

Private Sub SetupDataGridView()

    Me.Controls.Add(songsDataGridView)

    songsDataGridView.ColumnCount = 5
    With songsDataGridView.ColumnHeadersDefaultCellStyle
        .BackColor = Color.Navy
        .ForeColor = Color.White
        .Font = New Font(songsDataGridView.Font, FontStyle.Bold)
    End With

    With songsDataGridView
        .Name = "songsDataGridView"
        .Location = New Point(8, 8)
        .Size = New Size(500, 250)
        .AutoSizeRowsMode = _
            DataGridViewAutoSizeRowsMode.DisplayedCellsExceptHeaders
        .ColumnHeadersBorderStyle = DataGridViewHeaderBorderStyle.Single
        .CellBorderStyle = DataGridViewCellBorderStyle.Single
        .GridColor = Color.Black
        .RowHeadersVisible = False

        .Columns(0).Name = "Release Date"
        .Columns(1).Name = "Track"
        .Columns(2).Name = "Title"
        .Columns(3).Name = "Artist"
        .Columns(4).Name = "Album"
        .Columns(4).DefaultCellStyle.Font = _
            New Font(Me.songsDataGridView.DefaultCellStyle.Font, FontStyle.Italic)

        .SelectionMode = DataGridViewSelectionMode.FullRowSelect
        .MultiSelect = False
        .Dock = DockStyle.Fill
    End With

End Sub

private void SetupDataGridView()
{
    this.Controls.Add(songsDataGridView);

    songsDataGridView.ColumnCount = 5;

    songsDataGridView.ColumnHeadersDefaultCellStyle.BackColor = Color.Navy;
    songsDataGridView.ColumnHeadersDefaultCellStyle.ForeColor = Color.White;
    songsDataGridView.ColumnHeadersDefaultCellStyle.Font =
        new Font(songsDataGridView.Font, FontStyle.Bold);

    songsDataGridView.Name = "songsDataGridView";
    songsDataGridView.Location = new Point(8, 8);
    songsDataGridView.Size = new Size(500, 250);
    songsDataGridView.AutoSizeRowsMode =
        DataGridViewAutoSizeRowsMode.DisplayedCellsExceptHeaders;
    songsDataGridView.ColumnHeadersBorderStyle =
        DataGridViewHeaderBorderStyle.Single;
    songsDataGridView.CellBorderStyle = DataGridViewCellBorderStyle.Single;
    songsDataGridView.GridColor = Color.Black;
    songsDataGridView.RowHeadersVisible = false;

    songsDataGridView.Columns[0].Name = "Release Date";
    songsDataGridView.Columns[1].Name = "Track";
    songsDataGridView.Columns[2].Name = "Title";
    songsDataGridView.Columns[3].Name = "Artist";
    songsDataGridView.Columns[4].Name = "Album";
    songsDataGridView.Columns[4].DefaultCellStyle.Font =
        new Font(songsDataGridView.DefaultCellStyle.Font, FontStyle.Italic);

    songsDataGridView.SelectionMode =
        DataGridViewSelectionMode.FullRowSelect;
    songsDataGridView.MultiSelect = false;
    songsDataGridView.Dock = DockStyle.Fill;

    songsDataGridView.CellFormatting += new
        DataGridViewCellFormattingEventHandler(
        songsDataGridView_CellFormatting);
}

Create a PopulateDataGridView method to add rows to the DataGridView control.

Each row represents a song and its associated information.

Private Sub PopulateDataGridView()

    Dim row0 As String() = {"11/22/1968", "29", "Revolution 9", _
        "Beatles", "The Beatles [White Album]"}
    Dim row1 As String() = {"1960", "6", "Fools Rush In", _
        "Frank Sinatra", "Nice 'N' Easy"}
    Dim row2 As String() = {"11/11/1971", "1", "One of These Days", _
        "Pink Floyd", "Meddle"}
    Dim row3 As String() = {"1988", "7", "Where Is My Mind?", _
        "Pixies", "Surfer Rosa"}
    Dim row4 As String() = {"5/1981", "9", "Can't Find My Mind", _
        "Cramps", "Psychedelic Jungle"}
    Dim row5 As String() = {"6/10/2003", "13", _
        "Scatterbrain. (As Dead As Leaves.)", _
        "Radiohead", "Hail to the Thief"}
    Dim row6 As String() = {"6/30/1992", "3", "Dress", "P J Harvey", "Dry"}

    With Me.songsDataGridView.Rows
        .Add(row0)
        .Add(row1)
        .Add(row2)
        .Add(row3)
        .Add(row4)
        .Add(row5)
        .Add(row6)
    End With

    With Me.songsDataGridView
        .Columns(0).DisplayIndex = 3
        .Columns(1).DisplayIndex = 4
        .Columns(2).DisplayIndex = 0
        .Columns(3).DisplayIndex = 1
        .Columns(4).DisplayIndex = 2
    End With

End Sub

private void PopulateDataGridView()
{

    string[] row0 = { "11/22/1968", "29", "Revolution 9", 
        "Beatles", "The Beatles [White Album]" };
    string[] row1 = { "1960", "6", "Fools Rush In", 
        "Frank Sinatra", "Nice 'N' Easy" };
    string[] row2 = { "11/11/1971", "1", "One of These Days", 
        "Pink Floyd", "Meddle" };
    string[] row3 = { "1988", "7", "Where Is My Mind?", 
        "Pixies", "Surfer Rosa" };
    string[] row4 = { "5/1981", "9", "Can't Find My Mind", 
        "Cramps", "Psychedelic Jungle" };
    string[] row5 = { "6/10/2003", "13", 
        "Scatterbrain. (As Dead As Leaves.)", 
        "Radiohead", "Hail to the Thief" };
    string[] row6 = { "6/30/1992", "3", "Dress", "P J Harvey", "Dry" };

    songsDataGridView.Rows.Add(row0);
    songsDataGridView.Rows.Add(row1);
    songsDataGridView.Rows.Add(row2);
    songsDataGridView.Rows.Add(row3);
    songsDataGridView.Rows.Add(row4);
    songsDataGridView.Rows.Add(row5);
    songsDataGridView.Rows.Add(row6);

    songsDataGridView.Columns[0].DisplayIndex = 3;
    songsDataGridView.Columns[1].DisplayIndex = 4;
    songsDataGridView.Columns[2].DisplayIndex = 0;
    songsDataGridView.Columns[3].DisplayIndex = 1;
    songsDataGridView.Columns[4].DisplayIndex = 2;
}

With the utility methods in place, you can attach event handlers.

You will handle the Add and Delete buttons' Click events, the form's Load event, and the DataGridView control's CellFormatting event.

When the Add button's Click event is raised, a new, empty row is added to the DataGridView.

When the Delete button's Click event is raised, the selected row is deleted, unless it is the row for new records, which enables the user add new rows. This row is always the last row in the DataGridView control.

When the form's Load event is raised, the SetupLayout, SetupDataGridView, and PopulateDataGridView utility methods are called.

When the CellFormatting event is raised, each cell in the Date column is formatted as a long date, unless the cell's value cannot be parsed.

Private Sub Form1_Load(ByVal sender As System.Object, _
    ByVal e As System.EventArgs) Handles MyBase.Load

    SetupLayout()
    SetupDataGridView()
    PopulateDataGridView()

End Sub

Private Sub songsDataGridView_CellFormatting(ByVal sender As Object, _
    ByVal e As System.Windows.Forms.DataGridViewCellFormattingEventArgs) _
    Handles songsDataGridView.CellFormatting

    If e IsNot Nothing Then

        If Me.songsDataGridView.Columns(e.ColumnIndex).Name = _
        "Release Date" Then
            If e.Value IsNot Nothing Then
                Try
                    e.Value = DateTime.Parse(e.Value.ToString()) _
                        .ToLongDateString()
                    e.FormattingApplied = True
                Catch ex As FormatException
                    Console.WriteLine("{0} is not a valid date.", e.Value.ToString())
                End Try
            End If
        End If

    End If

End Sub

Private Sub addNewRowButton_Click(ByVal sender As Object, _
    ByVal e As EventArgs) Handles addNewRowButton.Click

    Me.songsDataGridView.Rows.Add()

End Sub

Private Sub deleteRowButton_Click(ByVal sender As Object, _
    ByVal e As EventArgs) Handles deleteRowButton.Click

    If Me.songsDataGridView.SelectedRows.Count > 0 AndAlso _
        Not Me.songsDataGridView.SelectedRows(0).Index = _
        Me.songsDataGridView.Rows.Count - 1 Then

        Me.songsDataGridView.Rows.RemoveAt( _
            Me.songsDataGridView.SelectedRows(0).Index)

    End If

End Sub

public Form1()
{
    this.Load += new EventHandler(Form1_Load);
}

private void Form1_Load(System.Object sender, System.EventArgs e)
{
    SetupLayout();
    SetupDataGridView();
    PopulateDataGridView();
}

private void songsDataGridView_CellFormatting(object sender,
    System.Windows.Forms.DataGridViewCellFormattingEventArgs e)
{
    if (e != null)
    {
        if (this.songsDataGridView.Columns[e.ColumnIndex].Name == "Release Date")
        {
            if (e.Value != null)
            {
                try
                {
                    e.Value = DateTime.Parse(e.Value.ToString())
                        .ToLongDateString();
                    e.FormattingApplied = true;
                }
                catch (FormatException)
                {
                    Console.WriteLine("{0} is not a valid date.", e.Value.ToString());
                }
            }
        }
    }
}

private void addNewRowButton_Click(object sender, EventArgs e)
{
    this.songsDataGridView.Rows.Add();
}

private void deleteRowButton_Click(object sender, EventArgs e)
{
    if (this.songsDataGridView.SelectedRows.Count > 0 &&
        this.songsDataGridView.SelectedRows[0].Index !=
        this.songsDataGridView.Rows.Count - 1)
    {
        this.songsDataGridView.Rows.RemoveAt(
            this.songsDataGridView.SelectedRows[0].Index);
    }
}

Testing the Application

You can now test the form to make sure it behaves as expected.

To test the form

Press F5 to run the application.

You will see a DataGridView control that displays the songs listed in PopulateDataGridView. You can add new rows with the Add Row button, and you can delete selected rows with the Delete Row button. The unbound DataGridView control is the data store, and its data is independent of any external source, such as a DataSet or an array.

Next Steps

This application gives you a basic understanding of the DataGridView control's capabilities. You can customize the appearance and behavior of the DataGridView control in several ways:

Change border and header styles. For more information, see How to: Change the Border and Gridline Styles in the Windows Forms DataGridView Control.
Enable or restrict user input to the DataGridView control. For more information, see How to: Prevent Row Addition and Deletion in the Windows Forms DataGridView Control, and How to: Make Columns Read-Only in the Windows Forms DataGridView Control.
Check user input for database-related errors. For more information, see Walkthrough: Handling Errors that Occur During Data Entry in the Windows Forms DataGridView Control.
Handle very large data sets using virtual mode. For more information, see Walkthrough: Implementing Virtual Mode in the Windows Forms DataGridView Control.
Customize the appearance of cells. For more information, see How to: Customize the Appearance of Cells in the Windows Forms DataGridView Control and How to: Set Default Cell Styles for the Windows Forms DataGridView Control.

Dela via

Walkthrough: Creating an Unbound Windows Forms DataGridView Control

Creating the Form

To use an unbound DataGridView control

Testing the Application

To test the form

Next Steps

See Also

Tasks

Reference

Concepts

Other Resources

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