datagridview-image-column ソースコード全文

<Solution>
  <Project Path="DataGridView_Image_Column/DataGridView_Image_Column.csproj" />
</Solution>

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net10.0-windows</TargetFramework>
    <Nullable>enable</Nullable>
    <UseWindowsForms>true</UseWindowsForms>
    <ImplicitUsings>enable</ImplicitUsings>
  </PropertyGroup>

  <ItemGroup>
    <None Update="apple.png">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update="orange.png">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
  </ItemGroup>

</Project>

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="Current" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <ItemGroup>
        <Compile Update="Form1.cs">
            <SubType>Form</SubType>
        </Compile>
    </ItemGroup>
</Project>

using System.ComponentModel;

namespace DataGridView_Image_Column
{
    public partial class Form1 : Form
    {
        private BindingList<ProductModel> _products = new();

        public Form1()
        {
            InitializeComponent();
            InitializeDataGridView();
        }

        private void InitializeDataGridView()
        {
            // テスト用の画像ファイルを読み込み（※パスは環境に合わせて変更してください）
            // 画像がない（Null）パターンの検証用データも登録します
            Image? imgApple = File.Exists("apple.png") ? Image.FromFile("apple.png") : null;
            Image? imgOrange = File.Exists("orange.png") ? Image.FromFile("orange.png") : null;

            _products.Add(new ProductModel("P001", "りんご", imgApple));
            _products.Add(new ProductModel("P002", "みかん", imgOrange));
            _products.Add(new ProductModel("P003", "バナナ（画像なし）", null)); // ⭕ 画像Nullのデータ

            // 1. 手動で画像列を作成
            var imageCol = new DataGridViewImageColumn();
            imageCol.DataPropertyName = nameof(ProductModel.ProductImage); // モデルのImageプロパティと連動
            imageCol.HeaderText = "商品画像";
            imageCol.Name = "ProductImage";

            // 2. 【対策①】画像がNullのときに表示される不格好な「×マーク」を消す設定
            // デフォルトの「エラー画像」の代わりに空白の透過ビットマップを指定します
            var blankImage = new Bitmap(1, 1);
            imageCol.DefaultCellStyle.NullValue = blankImage;

            // 3. 【対策②】画像のサイズ調整（アスペクト比を維持してセルの大きさに合わせる）
            imageCol.ImageLayout = DataGridViewImageCellLayout.Zoom;

            // 画像列をグリッドに追加
            dataGridView1.Columns.Add(imageCol);

            // 4. その他の列を自動生成してデータソースを設定
            dataGridView1.DataSource = _products;

            // 画像が見やすくなるように、行の高さと列幅を少し広げる
            dataGridView1.RowTemplate.Height = 60;
            dataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;
        }
    }
}

namespace DataGridView_Image_Column
{
    partial class Form1
    {
        /// <summary>
        ///  Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        ///  Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        ///  Required method for Designer support - do not modify
        ///  the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {
            dataGridView1 = new DataGridView();
            ((System.ComponentModel.ISupportInitialize)dataGridView1).BeginInit();
            SuspendLayout();
            //
            // dataGridView1
            //
            dataGridView1.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            dataGridView1.Dock = DockStyle.Fill;
            dataGridView1.Location = new Point(0, 0);
            dataGridView1.Name = "dataGridView1";
            dataGridView1.RowHeadersWidth = 62;
            dataGridView1.Size = new Size(800, 450);
            dataGridView1.TabIndex = 0;
            //
            // Form1
            //
            AutoScaleDimensions = new SizeF(10F, 25F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(800, 450);
            Controls.Add(dataGridView1);
            Name = "Form1";
            Text = "Form1";
            ((System.ComponentModel.ISupportInitialize)dataGridView1).EndInit();
            ResumeLayout(false);
        }

        #endregion

        private DataGridView dataGridView1;
    }
}

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namespace DataGridView_Image_Column
{
    public class ProductModel
    {
        public string Code { get; set; }
        public string Name { get; set; }

        // 画像オブジェクトを保持するプロパティ（Nullを許容します）
        public Image? ProductImage { get; set; }

        public ProductModel(string code, string name, Image? productImage)
        {
            Code = code;
            Name = name;
            ProductImage = productImage;
        }
    }
}

namespace DataGridView_Image_Column
{
    internal static class Program
    {
        /// <summary>
        ///  The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            // To customize application configuration such as set high DPI settings or default font,
            // see https://aka.ms/applicationconfiguration.
            ApplicationConfiguration.Initialize();
            Application.Run(new Form1());
        }
    }
}