章立民研究室

圖表1

一般來說，每一個欄位的內容會單獨顯示於 DataGridView 控制項的一個資料行中。問題是，某些欄位擁有大量文字資料，我是不是能夠讓該欄位的內容以跨資料行的方式來顯示，以便在有限的畫面空間中的呈現出更完整的內容呢？答案當然是肯定的。 

以圖表 1 所示的執行畫面而言，「自傳」欄位的內容並未單獨顯示於一個資料行中，而是以橫跨資料行的方式，顯示在同筆資料列之各欄位內容的下方。相關程式碼列示如下： 

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
…
…
…
private int oldRowIndex = 0;
private const int CUSTOM_CONTENT_HEIGHT = 80;
private DataSet myDataSet;

private void CH13_DemoForm009_Load(object sender, EventArgs e)
{
    Padding newPadding = new Padding(0, 1, 0, CUSTOM_CONTENT_HEIGHT);
    this.DataGridView1.RowTemplate.DefaultCellStyle.Padding = newPadding;

    this.DataGridView1.RowTemplate.DefaultCellStyle.SelectionBackColor =
        Color.Transparent;

    this.DataGridView1.RowTemplate.Height += CUSTOM_CONTENT_HEIGHT;

    this.DataGridView1.AllowUserToAddRows = false;
    this.DataGridView1.EditMode = DataGridViewEditMode.EditOnKeystrokeOrF2;
    this.DataGridView1.CellBorderStyle = DataGridViewCellBorderStyle.None;
    this.DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect;

    myDataSet = LoadDataToDataSet();

    if(myDataSet != null)
    {
        // 將 BindingSource 元件繫結至資料集物件中的「飛狐工作室」資料表。
        this.BindingSource1.DataMember = "飛狐工作室";
        this.BindingSource1.DataSource = myDataSet;

        this.BindingSource1.AllowNew = false;

        // 將 BindingNavigator 控制項的資料來源也設定成 BindingSource 元件
        //，如此一來，就可以使用 BindingNavigator 控制項去導覽
        // DataGridView 控制項中的資料列。
        this.BindingNavigator1.BindingSource = this.BindingSource1;

        this.DataGridView1.DataSource = this.BindingSource1;
    }
    else
    {
        return;
    }

    this.DataGridView1.Columns[4].Visible = false;

    this.DataGridView1.Columns[0].SortMode =
         DataGridViewColumnSortMode.NotSortable;
    this.DataGridView1.Columns[2].SortMode =
         DataGridViewColumnSortMode.NotSortable;
    this.DataGridView1.Columns[3].SortMode =
         DataGridViewColumnSortMode.NotSortable;

    this.DataGridView1.AutoResizeRows(
        DataGridViewAutoSizeRowsMode.AllCellsExceptHeaders);
}

private void DataGridView1_ColumnWidthChanged(object sender,
                                         DataGridViewColumnEventArgs e)
{
    this.DataGridView1.Invalidate();
}

private void DataGridView1_CurrentCellChanged(object sender, EventArgs e)
{
    if(oldRowIndex != -1)
    {
        this.DataGridView1.InvalidateRow(oldRowIndex);
    }

    oldRowIndex = this.DataGridView1.CurrentCellAddress.Y;
}

private void DataGridView1_RowPrePaint(object sender,
                            DataGridViewRowPrePaintEventArgs e)
{
    e.PaintParts = e.PaintParts & (~DataGridViewPaintParts.Focus);

    if((e.State & DataGridViewElementStates.Selected) ==
                                DataGridViewElementStates.Selected)
    {
        Rectangle rowBounds = new Rectangle(
            this.DataGridView1.RowHeadersWidth, e.RowBounds.Top,
            this.DataGridView1.Columns.GetColumnsWidth(
            DataGridViewElementStates.Visible) -
            this.DataGridView1.HorizontalScrollingOffset + 1,
            e.RowBounds.Height);

        System.Drawing.Drawing2D.LinearGradientBrush backbrush =
            new System.Drawing.Drawing2D.LinearGradientBrush(rowBounds,
            this.DataGridView1.DefaultCellStyle.SelectionBackColor,
            e.InheritedRowStyle.ForeColor,
            System.Drawing.Drawing2D.LinearGradientMode.Horizontal);

        try
        {
            e.Graphics.FillRectangle(backbrush, rowBounds);
        }
        finally
        {
            backbrush.Dispose();
        }
    }
}

private void DataGridView1_RowPostPaint(object sender,
                               DataGridViewRowPostPaintEventArgs e)
{
    Rectangle rowBounds = new Rectangle(this.DataGridView1.RowHeadersWidth,
        e.RowBounds.Top, this.DataGridView1.Columns.GetColumnsWidth(
   
    DataGridViewElementStates.Visible) -
        this.DataGridView1.HorizontalScrollingOffset + 1, e.RowBounds.Height);

    SolidBrush forebrush = null;

    try
    {
        if((e.State & DataGridViewElementStates.Selected) ==
            DataGridViewElementStates.Selected)
        {
            forebrush = new SolidBrush(e.InheritedRowStyle.SelectionForeColor);
        }
        else
        {
            forebrush = new SolidBrush(e.InheritedRowStyle.ForeColor);
        }

        Object recipe =
          this.DataGridView1.Rows.SharedRow(e.RowIndex).Cells[4].Value;

        if(!(recipe == null))
        {
            string text = recipe.ToString();
            Rectangle textArea = rowBounds;
            RectangleF clip = textArea;

            textArea.X -= this.DataGridView1.HorizontalScrollingOffset;
            textArea.Width += this.DataGridView1.HorizontalScrollingOffset;
            textArea.Y += rowBounds.Height - e.InheritedRowStyle.Padding.Bottom;
            textArea.Height -= rowBounds.Height -
                                   e.InheritedRowStyle.Padding.Bottom;
            textArea.Height =
               (textArea.Height / e.InheritedRowStyle.Font.Height) *
                e.InheritedRowStyle.Font.Height;
           
            clip.Width -= this.DataGridView1.RowHeadersWidth + 1 - clip.X;
            clip.X = this.DataGridView1.RowHeadersWidth + 1;
                  
            RectangleF oldClip = e.Graphics.ClipBounds;

            e.Graphics.SetClip(clip);

            e.Graphics.DrawString(text, e.InheritedRowStyle.Font,
                                  forebrush, textArea);

            e.Graphics.SetClip(oldClip);
        }
    }
    finally
    {
        forebrush.Dispose();
    }

    if (this.DataGridView1.CurrentCellAddress.Y == e.RowIndex)
    {
        e.DrawFocus(rowBounds, true);
    }
}

private void DataGridView1_RowHeightChanged(
                    object sender, DataGridViewRowEventArgs e)
{
    int preferredNormalContentHeight =
        e.Row.GetPreferredHeight(e.Row.Index,
        DataGridViewAutoSizeRowMode.AllCellsExceptHeader, true) -
        e.Row.DefaultCellStyle.Padding.Bottom;

    Padding newPadding = e.Row.DefaultCellStyle.Padding;
           
    newPadding.Bottom = e.Row.Height - preferredNormalContentHeight;
    e.Row.DefaultCellStyle.Padding = newPadding;
}

// 本程序會連接至資料來源並建立所需的 DataSet 物件。
private DataSet LoadDataToDataSet()
{
    // 利用 SqlConnectionStringBuilder 物件來構建連接字串。
    SqlConnectionStringBuilder sqlStringBuilder =
        new SqlConnectionStringBuilder();

    sqlStringBuilder.DataSource = @"(local)SQLEXPRESS";
    sqlStringBuilder.InitialCatalog = "北風貿易";
    sqlStringBuilder.IntegratedSecurity = true;

    // 建立一個資料集。
    DataSet ds = new DataSet();

    try
    {
        using (SqlConnection northwindConnection =
            new SqlConnection(sqlStringBuilder.ConnectionString))
        {
            SqlCommand cmdLiming = new SqlCommand(
              "SELECT 姓名,員工性別,出生日期, 目前薪資, 自傳" +
              " FROM dbo.飛狐工作室 WHERE 自傳 IS NOT NULL",
              northwindConnection);

            northwindConnection.Open();

            using (SqlDataReader drLiming = cmdLiming.ExecuteReader())
            {
                ds.Load(
                  drLiming,
                  LoadOption.OverwriteChanges,
                  new string[] { "飛狐工作室" });
            }
        }
    }
    catch (Exception)
    {
        MessageBox.Show(
            "要能夠順利執行本範例程式，您的電腦必須已安裝 SQL Server " +
            "Express，並且必須已附加了本書所附的「北風貿易」資料庫。" +
            "關於如何安裝 SQL Server Express，請參閱附錄或相關文件說明。");

        // 無法連接至 SQL Server。
        return null;
    }

    return ds;
} 

建議閱讀書籍：「Visual C# 2005 檔案IO 與資料存取秘訣」