Windows Forms を使用して DataGridView で CURD を完成させる

2023年8月4日#Windows Forms50

AI 翻訳

この記事はAIを通じて英語から日本語に翻訳されました。原文を表示

AI が生成した要約

DataGridView 控件展示数据（内存）的 Minimum CRUD Demo，包括双缓冲机制、添加、更新、删除数据行的功能。

データを表示するために DataGridView コントロールを使用する（メモリ内）、最小限の CRUD デモを完成させる：

DataGridViewExtentions.cs#

using System.Reflection;

namespace ConsoleApp.WindowsFormTests
{
    public static class ExtensionMethods
    {
        // ダブルバッファリング機能を有効にし、UI コントロールの再描画時のちらつきを減らす
        public static void DoubleBuffered(this DataGridView dgv, bool setting)
        {
            Type dgvType = dgv.GetType();
            PropertyInfo? pi = dgvType.GetProperty("DoubleBuffered", BindingFlags.Instance | BindingFlags.NonPublic);
            pi!.SetValue(dgv, setting, null);
        }
    }
}

FrmMain.cs#

using System.Data;

namespace ConsoleApp.WindowsFormTests
{
    public partial class FrmMain : Form
    {
        public FrmMain()
        {
            InitializeComponent();
        }

        private readonly DataTable _dataTable = new();

        private void FrmMain_Load(object sender, EventArgs e)
        {
            InitialDataTable();
            InitalDataGridView();

            btnAdd.Click += BtnAdd_Click;
            btnUpdate.Click += BtnUpdate_Click;
            btnDelete.Click += BtnDelete_Click;
        }

        private void BtnDelete_Click(object? sender, EventArgs e)
        {
            if (!AnySelectedRow())
            {
                MessageBox.Show("削除する行を選択してください");
                return;
            }

            var row = GetSelectedRow();
            var id = row.Cells["Id"].Value;
            var nickName = row.Cells["NickName"].Value;

            var dialogResult = MessageBox.Show($"{nickName} を削除してもよろしいですか？", "削除確認", MessageBoxButtons.YesNo);
            if (dialogResult == DialogResult.No) return;

            DeleteDataRow(id);
            ClearDataGridViewSelection();
        }

        private void BtnUpdate_Click(object? sender, EventArgs e)
        {
            if (!AnySelectedRow())
            {
                MessageBox.Show("変更する行を選択してください");
                return;
            }

            var nickName = txtNickName.Text.Trim();
            if (string.IsNullOrWhiteSpace(nickName))
            {
                txtNickName.Focus();
                return;
            }

            var id = GetSelectedRow().Cells["Id"].Value;

            UpdateDataRow(id!, nickName);
        }
        private void BtnAdd_Click(object? sender, EventArgs e)
        {
            var nickName = txtNickName.Text.Trim();
            if (string.IsNullOrWhiteSpace(nickName))
            {
                txtNickName.Focus();
                return;
            }
            dataGridView1.ClearSelection();
            AddDataRow(nickName);

            // 初めてデータを追加すると、dataGridView は最初のデータを選択します。ここでデフォルトの選択をクリアします
            if (_dataTable.Rows.Count == 1)
            {
                ClearDataGridViewSelection();
            }

            txtNickName.Clear();
            txtNickName.Focus();
        }
        private void DataGridView1_SelectionChanged(object? sender, EventArgs e)
        {
            if (!AnySelectedRow()) return;

            var selectedRow = GetSelectedRow();
            txtNickName.Text = selectedRow.Cells["NickName"].Value.ToString();
        }

        private void AddDataRow(string nickName)
        {
            _dataTable.Rows.Add(Guid.NewGuid(), nickName);
        }
        private void UpdateDataRow(object? key, string nickName)
        {
            var row = _dataTable.Rows.Find(key);
            row!["NickName"] = nickName;
        }
        private void DeleteDataRow(object? key)
        {
            var row = _dataTable.Rows.Find(key);
            row!.Delete();
        }
        private void InitialDataTable()
        {
            var idColumn = _dataTable.Columns.Add("Id");
            _dataTable.Columns.Add("NickName");
            _dataTable.PrimaryKey = new DataColumn[] { idColumn };
        }
        private void InitalDataGridView()
        {
            dataGridView1.DataSource = _dataTable;
            dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
            dataGridView1.MultiSelect = false;
            dataGridView1.DoubleBuffered(true);

            dataGridView1.RowPrePaint += DataGridView1_RowPrePaint;
            dataGridView1.SelectionChanged += DataGridView1_SelectionChanged;
        }
        private void ClearDataGridViewSelection()
        {
            dataGridView1.ClearSelection();
            dataGridView1.CurrentCell = null;
        }
        private bool AnySelectedRow() => dataGridView1.CurrentRow != null;
        private DataGridViewRow GetSelectedRow() => dataGridView1.CurrentRow;
        // フォーカススタイルの描画を防ぎ、視覚効果を改善し、行がフォーカスなしでより一貫して見えるようにする
        private void DataGridView1_RowPrePaint(object? sender, DataGridViewRowPrePaintEventArgs e) => e.PaintParts &= ~DataGridViewPaintParts.Focus;
    }
}

FrmMain.Designer.cs#

namespace ConsoleApp.WindowsFormTests
{
    partial class FrmMain
    {
        /// <summary>
        ///  必要なデザイナ変数。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        ///  使用中のリソースをクリーンアップします。
        /// </summary>
        /// <param name="disposing">管理リソースを解放する場合は true; それ以外は false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        ///  デザイナサポートのために必要なメソッド - このメソッドの内容をコードエディタで変更しないでください。
        /// </summary>
        private void InitializeComponent()
        {
            txtNickName = new TextBox();
            btnAdd = new Button();
            dataGridView1 = new DataGridView();
            btnUpdate = new Button();
            btnDelete = new Button();
            ((System.ComponentModel.ISupportInitialize)dataGridView1).BeginInit();
            SuspendLayout();
            // 
            // txtNickName
            // 
            txtNickName.Location = new Point(71, 47);
            txtNickName.Name = "txtNickName";
            txtNickName.Size = new Size(125, 27);
            txtNickName.TabIndex = 0;
            // 
            // btnAdd
            // 
            btnAdd.Location = new Point(235, 44);
            btnAdd.Name = "btnAdd";
            btnAdd.Size = new Size(114, 33);
            btnAdd.TabIndex = 1;
            btnAdd.Text = "追加";
            btnAdd.UseVisualStyleBackColor = true;
            // 
            // dataGridView1
            // 
            dataGridView1.AllowUserToAddRows = false;
            dataGridView1.AllowUserToDeleteRows = false;
            dataGridView1.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            dataGridView1.Dock = DockStyle.Bottom;
            dataGridView1.Location = new Point(0, 116);
            dataGridView1.Name = "dataGridView1";
            dataGridView1.ReadOnly = true;
            dataGridView1.RowHeadersWidth = 51;
            dataGridView1.Size = new Size(710, 392);
            dataGridView1.TabIndex = 2;
            // 
            // btnUpdate
            // 
            btnUpdate.Location = new Point(374, 44);
            btnUpdate.Name = "btnUpdate";
            btnUpdate.Size = new Size(114, 33);
            btnUpdate.TabIndex = 3;
            btnUpdate.Text = "更新";
            btnUpdate.UseVisualStyleBackColor = true;
            // 
            // btnDelete
            // 
            btnDelete.Location = new Point(513, 44);
            btnDelete.Name = "btnDelete";
            btnDelete.Size = new Size(114, 33);
            btnDelete.TabIndex = 4;
            btnDelete.Text = "削除";
            btnDelete.UseVisualStyleBackColor = true;
            // 
            // FrmMain
            // 
            AcceptButton = btnAdd;
            AutoScaleDimensions = new SizeF(9F, 20F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(710, 508);
            Controls.Add(btnDelete);
            Controls.Add(btnUpdate);
            Controls.Add(dataGridView1);
            Controls.Add(btnAdd);
            Controls.Add(txtNickName);
            FormBorderStyle = FormBorderStyle.FixedSingle;
            Name = "FrmMain";
            StartPosition = FormStartPosition.CenterScreen;
            Text = "メイン";
            Load += FrmMain_Load;
            ((System.ComponentModel.ISupportInitialize)dataGridView1).EndInit();
            ResumeLayout(false);
            PerformLayout();
        }

        #endregion

        private TextBox txtNickName;
        private Button btnAdd;
        private DataGridView dataGridView1;
        private Button btnUpdate;
        private Button btnDelete;
    }
}

using System.Data; namespace ConsoleApp.WindowsFormTests { public partial class FrmMain : Form { public FrmMain() { InitializeComponent(); } private readonly DataTable _dataTable = new(); private void FrmMain_Load(object sender, EventArgs e) { InitialDataTable(); InitalDataGridView(); btnAdd.Click += BtnAdd_Click; btnUpdate.Click += BtnUpdate_Click; btnDelete.Click += BtnDelete_Click; } private void BtnDelete_Click(object? sender, EventArgs e) { if (!AnySelectedRow()) { MessageBox.Show("削除する行を選択してください"); return; } var row = GetSelectedRow(); var id = row.Cells["Id"].Value; var nickName = row.Cells["NickName"].Value; var dialogResult = MessageBox.Show($"{nickName} を削除してもよろしいですか？", "削除確認", MessageBoxButtons.YesNo); if (dialogResult == DialogResult.No) return; DeleteDataRow(id); ClearDataGridViewSelection(); } private void BtnUpdate_Click(object? sender, EventArgs e) { if (!AnySelectedRow()) { MessageBox.Show("変更する行を選択してください"); return; } var nickName = txtNickName.Text.Trim(); if (string.IsNullOrWhiteSpace(nickName)) { txtNickName.Focus(); return; } var id = GetSelectedRow().Cells["Id"].Value; UpdateDataRow(id!, nickName); } private void BtnAdd_Click(object? sender, EventArgs e) { var nickName = txtNickName.Text.Trim(); if (string.IsNullOrWhiteSpace(nickName)) { txtNickName.Focus(); return; } dataGridView1.ClearSelection(); AddDataRow(nickName); // 初めてデータを追加すると、dataGridView は最初のデータを選択します。ここでデフォルトの選択をクリアします if (_dataTable.Rows.Count == 1) { ClearDataGridViewSelection(); } txtNickName.Clear(); txtNickName.Focus(); } private void DataGridView1_SelectionChanged(object? sender, EventArgs e) { if (!AnySelectedRow()) return; var selectedRow = GetSelectedRow(); txtNickName.Text = selectedRow.Cells["NickName"].Value.ToString(); } private void AddDataRow(string nickName) { _dataTable.Rows.Add(Guid.NewGuid(), nickName); } private void UpdateDataRow(object? key, string nickName) { var row = _dataTable.Rows.Find(key); row!["NickName"] = nickName; } private void DeleteDataRow(object? key) { var row = _dataTable.Rows.Find(key); row!.Delete(); } private void InitialDataTable() { var idColumn = _dataTable.Columns.Add("Id"); _dataTable.Columns.Add("NickName"); _dataTable.PrimaryKey = new DataColumn[] { idColumn }; } private void InitalDataGridView() { dataGridView1.DataSource = _dataTable; dataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect; dataGridView1.MultiSelect = false; dataGridView1.DoubleBuffered(true); dataGridView1.RowPrePaint += DataGridView1_RowPrePaint; dataGridView1.SelectionChanged += DataGridView1_SelectionChanged; } private void ClearDataGridViewSelection() { dataGridView1.ClearSelection(); dataGridView1.CurrentCell = null; } private bool AnySelectedRow() => dataGridView1.CurrentRow != null; private DataGridViewRow GetSelectedRow() => dataGridView1.CurrentRow; // フォーカススタイルの描画を防ぎ、視覚効果を改善し、行がフォーカスなしでより一貫して見えるようにする private void DataGridView1_RowPrePaint(object? sender, DataGridViewRowPrePaintEventArgs e) => e.PaintParts &= ~DataGridViewPaintParts.Focus; } }

namespace ConsoleApp.WindowsFormTests { partial class FrmMain { /// <summary> /// 必要なデザイナ変数。 /// </summary> private System.ComponentModel.IContainer components = null; /// <summary> /// 使用中のリソースをクリーンアップします。 /// </summary> /// <param name="disposing">管理リソースを解放する場合は true; それ以外は false。</param> protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code /// <summary> /// デザイナサポートのために必要なメソッド - このメソッドの内容をコードエディタで変更しないでください。 /// </summary> private void InitializeComponent() { txtNickName = new TextBox(); btnAdd = new Button(); dataGridView1 = new DataGridView(); btnUpdate = new Button(); btnDelete = new Button(); ((System.ComponentModel.ISupportInitialize)dataGridView1).BeginInit(); SuspendLayout(); // // txtNickName // txtNickName.Location = new Point(71, 47); txtNickName.Name = "txtNickName"; txtNickName.Size = new Size(125, 27); txtNickName.TabIndex = 0; // // btnAdd // btnAdd.Location = new Point(235, 44); btnAdd.Name = "btnAdd"; btnAdd.Size = new Size(114, 33); btnAdd.TabIndex = 1; btnAdd.Text = "追加"; btnAdd.UseVisualStyleBackColor = true; // // dataGridView1 // dataGridView1.AllowUserToAddRows = false; dataGridView1.AllowUserToDeleteRows = false; dataGridView1.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize; dataGridView1.Dock = DockStyle.Bottom; dataGridView1.Location = new Point(0, 116); dataGridView1.Name = "dataGridView1"; dataGridView1.ReadOnly = true; dataGridView1.RowHeadersWidth = 51; dataGridView1.Size = new Size(710, 392); dataGridView1.TabIndex = 2; // // btnUpdate // btnUpdate.Location = new Point(374, 44); btnUpdate.Name = "btnUpdate"; btnUpdate.Size = new Size(114, 33); btnUpdate.TabIndex = 3; btnUpdate.Text = "更新"; btnUpdate.UseVisualStyleBackColor = true; // // btnDelete // btnDelete.Location = new Point(513, 44); btnDelete.Name = "btnDelete"; btnDelete.Size = new Size(114, 33); btnDelete.TabIndex = 4; btnDelete.Text = "削除"; btnDelete.UseVisualStyleBackColor = true; // // FrmMain // AcceptButton = btnAdd; AutoScaleDimensions = new SizeF(9F, 20F); AutoScaleMode = AutoScaleMode.Font; ClientSize = new Size(710, 508); Controls.Add(btnDelete); Controls.Add(btnUpdate); Controls.Add(dataGridView1); Controls.Add(btnAdd); Controls.Add(txtNickName); FormBorderStyle = FormBorderStyle.FixedSingle; Name = "FrmMain"; StartPosition = FormStartPosition.CenterScreen; Text = "メイン"; Load += FrmMain_Load; ((System.ComponentModel.ISupportInitialize)dataGridView1).EndInit(); ResumeLayout(false); PerformLayout(); } #endregion private TextBox txtNickName; private Button btnAdd; private DataGridView dataGridView1; private Button btnUpdate; private Button btnDelete; } }