datagridview-check-is-new-row ソースコード全文

<Solution>
  <Project Path="DataGridView_Check_IsNewRow/DataGridView_Check_IsNewRow.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.Data;

namespace DataGridView_Check_IsNewRow
{
    public partial class Form1 : Form
    {
        private DataTable _dataTable = new DataTable();

        // ユーザーが最後に選択していた行インデックスを記憶する変数
        private int _lastSelectedRowIndex = -1;

        public Form1()
        {
            InitializeComponent();
            InitializeDataGridView();
            btnCheckStatus.Click += btnCheckStatus_Click;
        }

        private void InitializeDataGridView()
        {
            _dataTable.Columns.Add("Code", typeof(string));
            _dataTable.Columns.Add("Name", typeof(string));
            _dataTable.Rows.Add("P001", "ノートパソコン");

            dataGridView1.DataSource = _dataTable;
            dataGridView1.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;

            // 選択行が変わったときに、インデックスを記憶するイベントを購読
            dataGridView1.SelectionChanged += DataGridView1_SelectionChanged;
        }

        /// <summary>
        /// 選択行が変わったときに呼び出されるイベント
        /// </summary>
        private void DataGridView1_SelectionChanged(object? sender, EventArgs e)
        {
            // DataGridView自身、またはその内部にフォーカスがあるときだけ、現在の行位置を記憶します
            // これにより、ボタンがクリックされてフォーカスが逃げたときの「自動引き戻し」による行移動を無視できます
            if (dataGridView1.ContainsFocus && dataGridView1.CurrentRow != null)
            {
                _lastSelectedRowIndex = dataGridView1.CurrentRow.Index;
            }
        }

        /// <summary>
        /// 「新規行かを確認」ボタンのクリックイベント
        /// </summary>
        private void btnCheckStatus_Click(object? sender, EventArgs e)
        {
            // 記憶している行インデックスが有効かチェック
            if (_lastSelectedRowIndex == -1 || _lastSelectedRowIndex >= dataGridView1.RowCount)
            {
                MessageBox.Show("行が選択されていません。");
                return;
            }

            // CurrentRow（勝手に動いてしまうプロパティ）の代わりに、
            // 記憶しておいたインデックスから「本当にユーザーが選んでいた行」を直接取得します
            DataGridViewRow targetRow = dataGridView1.Rows[_lastSelectedRowIndex];

            // 1. 完全に空っぽの「新規入力用の最下行」である場合
            // 逃げる前のインデックスを捕まえているので、ボタンクリックでもここを通過します。
            if (targetRow.IsNewRow)
            {
                MessageBox.Show("【ステータス】未入力の新規行です（左端に * がある行です）。");
                return;
            }

            // 2. データバインド環境の場合
            if (dataGridView1.DataSource != null)
            {
                if (targetRow.DataBoundItem is DataRowView dataRowView)
                {
                    if (dataRowView.IsNew)
                    {
                        MessageBox.Show("【ステータス】現在新しく入力している最中（未確定）の新規行です！");
                    }
                    else
                    {
                        MessageBox.Show("【ステータス】データベース等から読み込まれた、既存の確定データ行です。");
                    }
                    return;
                }
            }
            else
            {
                // 3. 非バインド環境の場合
                if (dataGridView1.NewRowIndex != -1 && targetRow.Index == dataGridView1.NewRowIndex - 1)
                {
                    MessageBox.Show("【ステータス】現在新しく入力している最中（未確定）の新規行です！");
                    return;
                }
            }

            MessageBox.Show("【ステータス】データベース等から読み込まれた、既存の確定データ行です。");
        }
    }
}

namespace DataGridView_Check_IsNewRow
{
    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();
            tableLayoutPanel1 = new TableLayoutPanel();
            btnCheckStatus = new Button();
            ((System.ComponentModel.ISupportInitialize)dataGridView1).BeginInit();
            tableLayoutPanel1.SuspendLayout();
            SuspendLayout();
            //
            // dataGridView1
            //
            dataGridView1.ColumnHeadersHeightSizeMode = DataGridViewColumnHeadersHeightSizeMode.AutoSize;
            dataGridView1.Dock = DockStyle.Fill;
            dataGridView1.Location = new Point(3, 3);
            dataGridView1.Name = "dataGridView1";
            dataGridView1.RowHeadersWidth = 62;
            dataGridView1.Size = new Size(794, 373);
            dataGridView1.TabIndex = 0;
            //
            // tableLayoutPanel1
            //
            tableLayoutPanel1.ColumnCount = 1;
            tableLayoutPanel1.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50F));
            tableLayoutPanel1.Controls.Add(dataGridView1, 0, 0);
            tableLayoutPanel1.Controls.Add(btnCheckStatus, 0, 1);
            tableLayoutPanel1.Dock = DockStyle.Fill;
            tableLayoutPanel1.Location = new Point(0, 0);
            tableLayoutPanel1.Name = "tableLayoutPanel1";
            tableLayoutPanel1.RowCount = 2;
            tableLayoutPanel1.RowStyles.Add(new RowStyle(SizeType.Percent, 84.3822861F));
            tableLayoutPanel1.RowStyles.Add(new RowStyle(SizeType.Percent, 15.6177158F));
            tableLayoutPanel1.Size = new Size(800, 450);
            tableLayoutPanel1.TabIndex = 1;
            //
            // btnCheckStatus
            //
            btnCheckStatus.Dock = DockStyle.Fill;
            btnCheckStatus.Location = new Point(3, 382);
            btnCheckStatus.Name = "btnCheckStatus";
            btnCheckStatus.Size = new Size(794, 65);
            btnCheckStatus.TabIndex = 1;
            btnCheckStatus.Text = "新規行かを確認";
            btnCheckStatus.UseVisualStyleBackColor = true;
            //
            // Form1
            //
            AutoScaleDimensions = new SizeF(10F, 25F);
            AutoScaleMode = AutoScaleMode.Font;
            ClientSize = new Size(800, 450);
            Controls.Add(tableLayoutPanel1);
            Name = "Form1";
            Text = "Form1";
            ((System.ComponentModel.ISupportInitialize)dataGridView1).EndInit();
            tableLayoutPanel1.ResumeLayout(false);
            ResumeLayout(false);
        }

        #endregion

        private DataGridView dataGridView1;
        private TableLayoutPanel tableLayoutPanel1;
        private Button btnCheckStatus;
    }
}

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

    Version 2.0

    The primary goals of this format is to allow a simple XML format
    that is mostly human readable. The generation and parsing of the
    various data types are done through the TypeConverter classes
    associated with the data types.

    Example:

    ... ado.net/XML headers & schema ...
    <resheader name="resmimetype">text/microsoft-resx</resheader>
    <resheader name="version">2.0</resheader>
    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
        <value>[base64 mime encoded serialized .NET Framework object]</value>
    </data>
    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
        <comment>This is a comment</comment>
    </data>

    There are any number of "resheader" rows that contain simple
    name/value pairs.

    Each data row contains a name, and value. The row also contains a
    type or mimetype. Type corresponds to a .NET class that support
    text/value conversion through the TypeConverter architecture.
    Classes that don't support this are serialized and stored with the
    mimetype set.

    The mimetype is used for serialized objects, and tells the
    ResXResourceReader how to depersist the object. This is currently not
    extensible. For a given mimetype the value must be set accordingly:

    Note - application/x-microsoft.net.object.binary.base64 is the format
    that the ResXResourceWriter will generate, however the reader can
    read any of the formats listed below.

    mimetype: application/x-microsoft.net.object.binary.base64
    value   : The object must be serialized with
            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
            : and then encoded with base64 encoding.

    mimetype: application/x-microsoft.net.object.soap.base64
    value   : The object must be serialized with
            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
            : and then encoded with base64 encoding.

    mimetype: application/x-microsoft.net.object.bytearray.base64
    value   : The object must be serialized into a byte array
            : using a System.ComponentModel.TypeConverter
            : and then encoded with base64 encoding.
    -->
  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
    <xsd:element name="root" msdata:IsDataSet="true">
      <xsd:complexType>
        <xsd:choice maxOccurs="unbounded">
          <xsd:element name="metadata">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" />
              </xsd:sequence>
              <xsd:attribute name="name" use="required" type="xsd:string" />
              <xsd:attribute name="type" type="xsd:string" />
              <xsd:attribute name="mimetype" type="xsd:string" />
              <xsd:attribute ref="xml:space" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="assembly">
            <xsd:complexType>
              <xsd:attribute name="alias" type="xsd:string" />
              <xsd:attribute name="name" type="xsd:string" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="data">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
              </xsd:sequence>
              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
              <xsd:attribute ref="xml:space" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="resheader">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
              </xsd:sequence>
              <xsd:attribute name="name" type="xsd:string" use="required" />
            </xsd:complexType>
          </xsd:element>
        </xsd:choice>
      </xsd:complexType>
    </xsd:element>
  </xsd:schema>
  <resheader name="resmimetype">
    <value>text/microsoft-resx</value>
  </resheader>
  <resheader name="version">
    <value>2.0</value>
  </resheader>
  <resheader name="reader">
    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
  </resheader>
  <resheader name="writer">
    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
  </resheader>
</root>

namespace DataGridView_Check_IsNewRow
{
    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());
        }
    }
}