数据表单与自定义列

using System;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

public partial class MainForm : Form
{
    private OleDbDataAdapter _adapter;
    private DataTable _table;
    private OleDbConnection _conn;

    private string GetConnectionString()
    {
        string path = Path.Combine(Application.StartupPath, "Data", "demo.mdb");
        return "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path
            + ";Persist Security Info=False;";
    }

    private void LoadProducts()
    {
        if (_conn != null)
        {
            _conn.Dispose();
            _conn = null;
        }
        _conn = new OleDbConnection(GetConnectionString());
        _adapter = new OleDbDataAdapter("SELECT Id, Name, Category, Progress, ImagePath FROM Products", _conn);
        OleDbCommandBuilder builder = new OleDbCommandBuilder(_adapter);
        _adapter.InsertCommand = builder.GetInsertCommand();
        _adapter.UpdateCommand = builder.GetUpdateCommand();
        _adapter.DeleteCommand = builder.GetDeleteCommand();

        _table = new DataTable();
        _adapter.Fill(_table);
        this.dgvProducts.AutoGenerateColumns = true;
        this.dgvProducts.DataSource = _table;
    }

    private void MainForm_Load(object sender, EventArgs e)
    {
        LoadProducts();
    }
}

Imports System
Imports System.Data
Imports System.Data.OleDb
Imports System.Drawing
Imports System.IO
Imports System.Windows.Forms

Public Class MainForm
    Inherits Form

    Private _adapter As OleDbDataAdapter
    Private _table As DataTable
    Private _conn As OleDbConnection

    Private Function GetConnectionString() As String
        Dim path As String = Path.Combine(Application.StartupPath, "Data", "demo.mdb")
        Return "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & path &
            ";Persist Security Info=False;"
    End Function

    Private Sub LoadProducts()
        If _conn IsNot Nothing Then
            _conn.Dispose()
            _conn = Nothing
        End If
        _conn = New OleDbConnection(GetConnectionString())
        _adapter = New OleDbDataAdapter(
            "SELECT Id, Name, Category, Progress, ImagePath FROM Products", _conn)
        Dim builder As New OleDbCommandBuilder(_adapter)
        _adapter.InsertCommand = builder.GetInsertCommand()
        _adapter.UpdateCommand = builder.GetUpdateCommand()
        _adapter.DeleteCommand = builder.GetDeleteCommand()

        _table = New DataTable()
        _adapter.Fill(_table)
        Me.dgvProducts.AutoGenerateColumns = True
        Me.dgvProducts.DataSource = _table
    End Sub

    Private Sub MainForm_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        LoadProducts()
    End Sub
End Class

private void btnAdd_Click(object sender, EventArgs e)
{
    DataRow row = _table.NewRow();
    row["Name"] = "新商品";
    row["Category"] = "未分类";
    row["Progress"] = 0;
    row["ImagePath"] = "";
    _table.Rows.Add(row);
}

private void btnDelete_Click(object sender, EventArgs e)
{
    if (this.dgvProducts.CurrentRow == null || this.dgvProducts.CurrentRow.IsNewRow)
    {
        return;
    }
    // 绑定 DataTable 时须标记行删除，Rows.Remove 不会产生 Deleted 状态，Update 无法持久化
    DataRowView view = this.dgvProducts.CurrentRow.DataBoundItem as DataRowView;
    if (view != null)
    {
        view.Row.Delete();
    }
}

private void btnSave_Click(object sender, EventArgs e)
{
    this.dgvProducts.EndEdit();
    BindingContext[_table].EndCurrentEdit();
    _adapter.Update(_table);
    _table.AcceptChanges();
    MessageBox.Show("已保存到 Access。", "保存", MessageBoxButtons.OK, MessageBoxIcon.Information);
}

private void btnRefresh_Click(object sender, EventArgs e)
{
    LoadProducts();
}

Private Sub btnAdd_Click(sender As Object, e As EventArgs) Handles btnAdd.Click
    Dim row As DataRow = _table.NewRow()
    row("Name") = "新商品"
    row("Category") = "未分类"
    row("Progress") = 0
    row("ImagePath") = ""
    _table.Rows.Add(row)
End Sub

Private Sub btnDelete_Click(sender As Object, e As EventArgs) Handles btnDelete.Click
    If Me.dgvProducts.CurrentRow Is Nothing OrElse Me.dgvProducts.CurrentRow.IsNewRow Then
        Return
    End If
    ' 绑定 DataTable 时须标记行删除，Rows.Remove 不会产生 Deleted 状态，Update 无法持久化
    Dim view As DataRowView = TryCast(Me.dgvProducts.CurrentRow.DataBoundItem, DataRowView)
    If view IsNot Nothing Then
        view.Row.Delete()
    End If
End Sub

Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
    Me.dgvProducts.EndEdit()
    BindingContext(_table).EndCurrentEdit()
    _adapter.Update(_table)
    _table.AcceptChanges()
    MessageBox.Show("已保存到 Access。", "保存", MessageBoxButtons.OK, MessageBoxIcon.Information)
End Sub

Private Sub btnRefresh_Click(sender As Object, e As EventArgs) Handles btnRefresh.Click
    LoadProducts()
End Sub

private void AddButtonColumn()
{
    DataGridViewButtonColumn col = new DataGridViewButtonColumn();
    col.Name = "colAction";
    col.HeaderText = "操作";
    col.Text = "详情";
    col.UseColumnTextForButtonValue = true;
    col.Width = 70;
    this.dgvProducts.Columns.Add(col);
}

private void dgvProducts_CellContentClick(object sender, DataGridViewCellEventArgs e)
{
    if (e.RowIndex < 0)
    {
        return;
    }
    if (this.dgvProducts.Columns[e.ColumnIndex].Name != "colAction")
    {
        return;
    }
    object idObj = this.dgvProducts.Rows[e.RowIndex].Cells["Id"].Value;
    MessageBox.Show("当前行 Id = " + Convert.ToString(idObj), "详情");
}

Private Sub AddButtonColumn()
    Dim col As New DataGridViewButtonColumn()
    col.Name = "colAction"
    col.HeaderText = "操作"
    col.Text = "详情"
    col.UseColumnTextForButtonValue = True
    col.Width = 70
    Me.dgvProducts.Columns.Add(col)
End Sub

Private Sub dgvProducts_CellContentClick(sender As Object, e As DataGridViewCellEventArgs) _
    Handles dgvProducts.CellContentClick
    If e.RowIndex < 0 Then
        Return
    End If
    If Me.dgvProducts.Columns(e.ColumnIndex).Name <> "colAction" Then
        Return
    End If
    Dim idObj As Object = Me.dgvProducts.Rows(e.RowIndex).Cells("Id").Value
    MessageBox.Show("当前行 Id = " & Convert.ToString(idObj), "详情")
End Sub

private void SetupImageColumn()
{
    this.dgvProducts.AutoGenerateColumns = false;
    this.dgvProducts.Columns.Clear();

    this.dgvProducts.Columns.Add(new DataGridViewTextBoxColumn()
    {
        Name = "Id",
        DataPropertyName = "Id",
        HeaderText = "编号",
        Width = 60
    });
    this.dgvProducts.Columns.Add(new DataGridViewTextBoxColumn()
    {
        Name = "Name",
        DataPropertyName = "Name",
        HeaderText = "名称"
    });

    DataGridViewImageColumn imgCol = new DataGridViewImageColumn();
    imgCol.Name = "colThumb";
    imgCol.HeaderText = "图";
    imgCol.ImageLayout = DataGridViewImageCellLayout.Zoom;
    imgCol.Width = 64;
    this.dgvProducts.Columns.Add(imgCol);

    this.dgvProducts.DataSource = _table;
    FillThumbnails();
}

private void FillThumbnails()
{
    for (int i = 0; i < this.dgvProducts.Rows.Count; i++)
    {
        if (this.dgvProducts.Rows[i].IsNewRow)
        {
            continue;
        }
        string rel = Convert.ToString(_table.Rows[i]["ImagePath"]);
        string full = Path.Combine(Application.StartupPath, rel ?? "");
        if (!string.IsNullOrEmpty(rel) && File.Exists(full))
        {
            this.dgvProducts.Rows[i].Cells["colThumb"].Value = Image.FromFile(full);
        }
    }
}

Private Sub SetupImageColumn()
    Me.dgvProducts.AutoGenerateColumns = False
    Me.dgvProducts.Columns.Clear()

    Dim idCol As New DataGridViewTextBoxColumn()
    idCol.Name = "Id"
    idCol.DataPropertyName = "Id"
    idCol.HeaderText = "编号"
    idCol.Width = 60
    Me.dgvProducts.Columns.Add(idCol)

    Dim nameCol As New DataGridViewTextBoxColumn()
    nameCol.Name = "Name"
    nameCol.DataPropertyName = "Name"
    nameCol.HeaderText = "名称"
    Me.dgvProducts.Columns.Add(nameCol)

    Dim imgCol As New DataGridViewImageColumn()
    imgCol.Name = "colThumb"
    imgCol.HeaderText = "图"
    imgCol.ImageLayout = DataGridViewImageCellLayout.Zoom
    imgCol.Width = 64
    Me.dgvProducts.Columns.Add(imgCol)

    Me.dgvProducts.DataSource = _table
    FillThumbnails()
End Sub

Private Sub FillThumbnails()
    Dim i As Integer
    For i = 0 To Me.dgvProducts.Rows.Count - 1
        If Me.dgvProducts.Rows(i).IsNewRow Then
            Continue For
        End If
        Dim rel As String = Convert.ToString(_table.Rows(i)("ImagePath"))
        Dim full As String = Path.Combine(Application.StartupPath, If(rel, ""))
        If Not String.IsNullOrEmpty(rel) AndAlso File.Exists(full) Then
            Me.dgvProducts.Rows(i).Cells("colThumb").Value = Image.FromFile(full)
        End If
    Next
End Sub

private void AddProgressColumn()
{
    DataGridViewTextBoxColumn col = new DataGridViewTextBoxColumn();
    col.Name = "Progress";
    col.DataPropertyName = "Progress";
    col.HeaderText = "进度";
    col.Width = 120;
    col.ReadOnly = true;
    this.dgvProducts.Columns.Add(col);
    this.dgvProducts.CellPainting += dgvProducts_CellPaintingProgress;
}

private void dgvProducts_CellPaintingProgress(object sender, DataGridViewCellPaintingEventArgs e)
{
    if (e.RowIndex < 0 || e.ColumnIndex < 0)
    {
        return;
    }
    if (this.dgvProducts.Columns[e.ColumnIndex].Name != "Progress")
    {
        return;
    }
    e.PaintBackground(e.ClipBounds, true);
    int value = 0;
    if (e.Value != null && e.Value != DBNull.Value)
    {
        value = Convert.ToInt32(e.Value);
    }
    if (value < 0) value = 0;
    if (value > 100) value = 100;

    Rectangle bar = e.CellBounds;
    bar.Inflate(-4, -6);
    bar.Width = Math.Max(1, (int)(bar.Width * value / 100.0));
    e.Graphics.FillRectangle(Brushes.SteelBlue, bar);
    TextRenderer.DrawText(
        e.Graphics,
        value.ToString() + "%",
        e.CellStyle.Font,
        e.CellBounds,
        e.CellStyle.ForeColor,
        TextFormatFlags.HorizontalCenter | TextFormatFlags.VerticalCenter);
    e.Handled = true;
}

Private Sub AddProgressColumn()
    Dim col As New DataGridViewTextBoxColumn()
    col.Name = "Progress"
    col.DataPropertyName = "Progress"
    col.HeaderText = "进度"
    col.Width = 120
    col.ReadOnly = True
    Me.dgvProducts.Columns.Add(col)
    AddHandler Me.dgvProducts.CellPainting, AddressOf dgvProducts_CellPaintingProgress
End Sub

Private Sub dgvProducts_CellPaintingProgress(sender As Object, e As DataGridViewCellPaintingEventArgs)
    If e.RowIndex < 0 OrElse e.ColumnIndex < 0 Then
        Return
    End If
    If Me.dgvProducts.Columns(e.ColumnIndex).Name <> "Progress" Then
        Return
    End If
    e.PaintBackground(e.ClipBounds, True)
    Dim value As Integer = 0
    If e.Value IsNot Nothing AndAlso e.Value IsNot DBNull.Value Then
        value = Convert.ToInt32(e.Value)
    End If
    If value < 0 Then value = 0
    If value > 100 Then value = 100

    Dim bar As Rectangle = e.CellBounds
    bar.Inflate(-4, -6)
    bar.Width = Math.Max(1, CInt(bar.Width * value / 100.0))
    e.Graphics.FillRectangle(Brushes.SteelBlue, bar)
    TextRenderer.DrawText(
        e.Graphics,
        value.ToString() & "%",
        e.CellStyle.Font,
        e.CellBounds,
        e.CellStyle.ForeColor,
        TextFormatFlags.HorizontalCenter Or TextFormatFlags.VerticalCenter)
    e.Handled = True
End Sub

private void AddComboColumn()
{
    DataGridViewComboBoxColumn col = new DataGridViewComboBoxColumn();
    col.Name = "Category";
    col.DataPropertyName = "Category";
    col.HeaderText = "类别";
    col.FlatStyle = FlatStyle.Flat;
    col.Items.AddRange(new object[] { "未分类", "原料", "成品", "耗材" });
    col.Width = 100;
    this.dgvProducts.Columns.Add(col);
}

Private Sub AddComboColumn()
    Dim col As New DataGridViewComboBoxColumn()
    col.Name = "Category"
    col.DataPropertyName = "Category"
    col.HeaderText = "类别"
    col.FlatStyle = FlatStyle.Flat
    col.Items.AddRange(New Object() {"未分类", "原料", "成品", "耗材"})
    col.Width = 100
    Me.dgvProducts.Columns.Add(col)
End Sub