datagridview-add-row ソースコード全文

<Solution>
  <Project Path="DataGridView_AddRow/DataGridView_AddRow.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>

</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;
using System.Data;

namespace DataGridView_AddRow
{
    public partial class Form1 : Form
    {
        // ── フィールド変数 ──────────────────────────────
        // DataTable バインド用
        private DataTable _dataTable = new DataTable();

        // BindingList バインド用
        private BindingList<Product> _products = new BindingList<Product>();

        // ── コンストラクタ ──────────────────────────────
        public Form1()
        {
            InitializeComponent();

            // タブ①：バインドなし
            SetupNoBindTab();

            // タブ②：DataTable バインド
            SetupDataTableTab();

            // タブ③：BindingList バインド
            SetupBindingListTab();
        }

        // ════════════════════════════════════════════════
        // タブ①：バインドなし（Rows.Add で直接追加）
        // ════════════════════════════════════════════════
        private void SetupNoBindTab()
        {
            // 列を手動で追加
            dataGridViewNoBind.Columns.Add("ColID", "ID");
            dataGridViewNoBind.Columns.Add("ColName", "名前");
            dataGridViewNoBind.Columns.Add("ColAge", "年齢");
            dataGridViewNoBind.AllowUserToAddRows = false;

            // ボタンクリックで行を追加
            btnAddNoBind.Click += (s, e) =>
            {
                int nextId = dataGridViewNoBind.Rows.Count + 1;
                dataGridViewNoBind.Rows.Add(nextId, $"ユーザー{nextId}", 20 + nextId);
            };
        }

        // ════════════════════════════════════════════════
        // タブ②：DataTable バインド
        // ════════════════════════════════════════════════
        private void SetupDataTableTab()
        {
            // DataTable の列定義
            _dataTable.Columns.Add("ID", typeof(int));
            _dataTable.Columns.Add("Name", typeof(string));
            _dataTable.Columns.Add("Age", typeof(int));

            // 初期データ
            _dataTable.Rows.Add(1, "じゅんや", 23);
            _dataTable.Rows.Add(2, "きょうこ", 25);
            _dataTable.Rows.Add(3, "えみ", 24);

            // DataGridView にバインド
            dataGridViewDT.DataSource = _dataTable;
            dataGridViewDT.AllowUserToAddRows = false;

            // ボタンクリックで DataTable に行追加 → DataGridView に自動反映
            btnAddDT.Click += (s, e) =>
            {
                int nextId = _dataTable.Rows.Count + 1;
                DataRow newRow = _dataTable.NewRow();
                newRow["ID"] = nextId;
                newRow["Name"] = $"ユーザー{nextId}";
                newRow["Age"] = 20 + nextId;
                _dataTable.Rows.Add(newRow);
            };
        }

        // ════════════════════════════════════════════════
        // タブ③：BindingList バインド
        // ════════════════════════════════════════════════
        private void SetupBindingListTab()
        {
            // 初期データ
            _products.Add(new Product { ID = 1, Name = "リンゴ", Price = 150 });
            _products.Add(new Product { ID = 2, Name = "バナナ", Price = 100 });
            _products.Add(new Product { ID = 3, Name = "メロン", Price = 800 });

            // DataGridView にバインド
            dataGridViewBL.DataSource = _products;
            dataGridViewBL.AllowUserToAddRows = false;

            // ボタンクリックで BindingList にオブジェクト追加 → 自動反映
            btnAddBL.Click += (s, e) =>
            {
                int nextId = _products.Count + 1;
                _products.Add(new Product
                {
                    ID = nextId,
                    Name = $"商品{nextId}",
                    Price = nextId * 100
                });
            };
        }
    }

    // ── BindingList 用データクラス ──────────────────────
    public class Product
    {
        public int ID { get; set; }
        public string Name { get; set; } = string.Empty;
        public int Price { get; set; }

        // 【ポイント】引数付きコンストラクタを定義する場合は
        // 引数なしコンストラクタも明示的に書く必要があります。
        public Product() { }
    }
}

namespace DataGridView_AddRow
{
    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()
        {
            tabControl1 = new TabControl();
            tabPage1 = new TabPage();
            tabPage2 = new TabPage();
            tabPage3 = new TabPage();
            tableLayoutPanel1 = new TableLayoutPanel();
            tableLayoutPanel2 = new TableLayoutPanel();
            tableLayoutPanel3 = new TableLayoutPanel();
            dataGridViewNoBind = new DataGridView();
            dataGridViewDT = new DataGridView();
            dataGridViewBL = new DataGridView();
            btnAddNoBind = new Button();
            btnAddDT = new Button();
            btnAddBL = new Button();
            tabControl1.SuspendLayout();
            tabPage1.SuspendLayout();
            tabPage2.SuspendLayout();
            tabPage3.SuspendLayout();
            tableLayoutPanel1.SuspendLayout();
            tableLayoutPanel2.SuspendLayout();
            tableLayoutPanel3.SuspendLayout();
            ((System.ComponentModel.ISupportInitialize)dataGridViewNoBind).BeginInit();
            ((System.ComponentModel.ISupportInitialize)dataGridViewDT).BeginInit();
            ((System.ComponentModel.ISupportInitialize)dataGridViewBL).BeginInit();
            SuspendLayout();
            //
            // tabControl1
            //
            tabControl1.Controls.Add(tabPage1);
            tabControl1.Controls.Add(tabPage2);
            tabControl1.Controls.Add(tabPage3);
            tabControl1.Dock = DockStyle.Fill;
            tabControl1.Location = new Point(0, 0);
            tabControl1.Name = "tabControl1";
            tabControl1.SelectedIndex = 0;
            tabControl1.Size = new Size(800, 450);
            tabControl1.TabIndex = 0;
            //
            // tabPage1
            //
            tabPage1.Controls.Add(tableLayoutPanel1);
            tabPage1.Location = new Point(4, 34);
            tabPage1.Name = "tabPage1";
            tabPage1.Padding = new Padding(3);
            tabPage1.Size = new Size(792, 412);
            tabPage1.TabIndex = 0;
            tabPage1.Text = "バインドなし";
            tabPage1.UseVisualStyleBackColor = true;
            //
            // tabPage2
            //
            tabPage2.Controls.Add(tableLayoutPanel2);
            tabPage2.Location = new Point(4, 34);
            tabPage2.Name = "tabPage2";
            tabPage2.Padding = new Padding(3);
            tabPage2.Size = new Size(792, 412);
            tabPage2.TabIndex = 1;
            tabPage2.Text = "DataTable バインド";
            tabPage2.UseVisualStyleBackColor = true;
            //
            // tabPage3
            //
            tabPage3.Controls.Add(tableLayoutPanel3);
            tabPage3.Location = new Point(4, 34);
            tabPage3.Name = "tabPage3";
            tabPage3.Padding = new Padding(3);
            tabPage3.Size = new Size(792, 412);
            tabPage3.TabIndex = 2;
            tabPage3.Text = "BindingList バインド";
            tabPage3.UseVisualStyleBackColor = true;
            //
            // tableLayoutPanel1
            //
            tableLayoutPanel1.ColumnCount = 1;
            tableLayoutPanel1.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50F));
            tableLayoutPanel1.Controls.Add(dataGridViewNoBind, 0, 0);
            tableLayoutPanel1.Controls.Add(btnAddNoBind, 0, 1);
            tableLayoutPanel1.Dock = DockStyle.Fill;
            tableLayoutPanel1.Location = new Point(3, 3);
            tableLayoutPanel1.Name = "tableLayoutPanel1";
            tableLayoutPanel1.RowCount = 2;
            tableLayoutPanel1.RowStyles.Add(new RowStyle(SizeType.Percent, 88.423645F));
            tableLayoutPanel1.RowStyles.Add(new RowStyle(SizeType.Percent, 11.576355F));
            tableLayoutPanel1.Size = new Size(786, 406);
            tableLayoutPanel1.TabIndex = 0;
            //
            // tableLayoutPanel2
            //
            tableLayoutPanel2.ColumnCount = 1;
            tableLayoutPanel2.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50F));
            tableLayoutPanel2.Controls.Add(dataGridViewDT, 0, 0);
            tableLayoutPanel2.Controls.Add(btnAddDT, 0, 1);
            tableLayoutPanel2.Dock = DockStyle.Fill;
            tableLayoutPanel2.Location = new Point(3, 3);
            tableLayoutPanel2.Name = "tableLayoutPanel2";
            tableLayoutPanel2.RowCount = 2;
            tableLayoutPanel2.RowStyles.Add(new RowStyle(SizeType.Percent, 88.423645F));
            tableLayoutPanel2.RowStyles.Add(new RowStyle(SizeType.Percent, 11.576355F));
            tableLayoutPanel2.Size = new Size(786, 406);
            tableLayoutPanel2.TabIndex = 1;
            //
            // tableLayoutPanel3
            //
            tableLayoutPanel3.ColumnCount = 1;
            tableLayoutPanel3.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50F));
            tableLayoutPanel3.Controls.Add(dataGridViewBL, 0, 0);
            tableLayoutPanel3.Controls.Add(btnAddBL, 0, 1);
            tableLayoutPanel3.Dock = DockStyle.Fill;
            tableLayoutPanel3.Location = new Point(3, 3);
            tableLayoutPanel3.Name = "tableLayoutPanel3";
            tableLayoutPanel3.RowCount = 2;
            tableLayoutPanel3.RowStyles.Add(new RowStyle(SizeType.Percent, 88.423645F));
            tableLayoutPanel3.RowStyles.Add(new RowStyle(SizeType.Percent, 11.576355F));
            tableLayoutPanel3.Size = new Size(786, 406);
            tableLayoutPanel3.TabIndex = 1;
            //
            // dataGridViewNoBind
            //
            dataGridViewNoBind.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            dataGridViewNoBind.Dock = DockStyle.Fill;
            dataGridViewNoBind.Location = new Point(3, 3);
            dataGridViewNoBind.Name = "dataGridViewNoBind";
            dataGridViewNoBind.RowHeadersWidth = 62;
            dataGridViewNoBind.Size = new Size(780, 353);
            dataGridViewNoBind.TabIndex = 0;
            //
            // dataGridViewDT
            //
            dataGridViewDT.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            dataGridViewDT.Dock = DockStyle.Fill;
            dataGridViewDT.Location = new Point(3, 3);
            dataGridViewDT.Name = "dataGridViewDT";
            dataGridViewDT.RowHeadersWidth = 62;
            dataGridViewDT.Size = new Size(780, 353);
            dataGridViewDT.TabIndex = 0;
            //
            // dataGridViewBL
            //
            dataGridViewBL.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            dataGridViewBL.Dock = DockStyle.Fill;
            dataGridViewBL.Location = new Point(3, 3);
            dataGridViewBL.Name = "dataGridViewBL";
            dataGridViewBL.RowHeadersWidth = 62;
            dataGridViewBL.Size = new Size(780, 353);
            dataGridViewBL.TabIndex = 0;
            //
            // btnAddNoBind
            //
            btnAddNoBind.Dock = DockStyle.Fill;
            btnAddNoBind.Location = new Point(3, 362);
            btnAddNoBind.Name = "btnAddNoBind";
            btnAddNoBind.Size = new Size(780, 41);
            btnAddNoBind.TabIndex = 1;
            btnAddNoBind.Text = "ボタンクリックで行を追加";
            btnAddNoBind.UseVisualStyleBackColor = true;
            //
            // btnAddDT
            //
            btnAddDT.Dock = DockStyle.Fill;
            btnAddDT.Location = new Point(3, 362);
            btnAddDT.Name = "btnAddDT";
            btnAddDT.Size = new Size(780, 41);
            btnAddDT.TabIndex = 1;
            btnAddDT.Text = "ボタンクリックで DataTable に行追加 → DataGridView に自動反映";
            btnAddDT.UseVisualStyleBackColor = true;
            //
            // btnAddBL
            //
            btnAddBL.Dock = DockStyle.Fill;
            btnAddBL.Location = new Point(3, 362);
            btnAddBL.Name = "btnAddBL";
            btnAddBL.Size = new Size(780, 41);
            btnAddBL.TabIndex = 1;
            btnAddBL.Text = "ボタンクリックで BindingList にオブジェクト追加 → 自動反映";
            btnAddBL.UseVisualStyleBackColor = true;
            //
            // Form1
            //
            AutoScaleDimensions = new SizeF(10F, 25F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(800, 450);
            Controls.Add(tabControl1);
            Name = "Form1";
            Text = "Form1";
            tabControl1.ResumeLayout(false);
            tabPage1.ResumeLayout(false);
            tabPage2.ResumeLayout(false);
            tabPage3.ResumeLayout(false);
            tableLayoutPanel1.ResumeLayout(false);
            tableLayoutPanel2.ResumeLayout(false);
            tableLayoutPanel3.ResumeLayout(false);
            ((System.ComponentModel.ISupportInitialize)dataGridViewNoBind).EndInit();
            ((System.ComponentModel.ISupportInitialize)dataGridViewDT).EndInit();
            ((System.ComponentModel.ISupportInitialize)dataGridViewBL).EndInit();
            ResumeLayout(false);
        }

        #endregion

        private TabControl tabControl1;
        private TabPage tabPage1;
        private TabPage tabPage2;
        private TabPage tabPage3;
        private TableLayoutPanel tableLayoutPanel1;
        private TableLayoutPanel tableLayoutPanel2;
        private TableLayoutPanel tableLayoutPanel3;
        private DataGridView dataGridViewNoBind;
        private DataGridView dataGridViewDT;
        private DataGridView dataGridViewBL;
        private Button btnAddNoBind;
        private Button btnAddDT;
        private Button btnAddBL;
    }
}

<?xml version="1.0" encoding="utf-8"?>
<root>
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    Microsoft ResX Schema

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    The primary goals of this format is to allow a simple XML format
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    The mimetype is used for serialized objects, and tells the
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    mimetype: application/x-microsoft.net.object.binary.base64
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    mimetype: application/x-microsoft.net.object.bytearray.base64
    value   : The object must be serialized into a byte array
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              <xsd:attribute name="mimetype" type="xsd:string" />
              <xsd:attribute ref="xml:space" />
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          </xsd:element>
          <xsd:element name="assembly">
            <xsd:complexType>
              <xsd:attribute name="alias" type="xsd:string" />
              <xsd:attribute name="name" type="xsd:string" />
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          <xsd:element name="data">
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                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
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namespace DataGridView_AddRow
{
    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());
        }
    }
}