图表1
一般来说，每一个字段的内容会单独显示于DataGridView控件的一个数据行中。问题是，某些字段拥有大量文字数据，我是不是能够让该字段的内容以跨数据行的方式来显示，以便在有限的画面空间中的呈现出更完整的内容呢？答案当然是肯定的。
以图表1所示的执行画面而言，「自传」字段的内容并未单独显示于一个数据行中，而是以横跨数据行的方式，显示在同笔数据列之各字段内容的下方。相关程序代码列示如下：
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;
…
…
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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)
{
// 将 BindingSource 组件系结至数据集对象中的「飞狐工作室」数据表。
this.BindingSource1.DataMember = "飞狐工作室";
this.BindingSource1.DataSource = myDataSet;
this.BindingSource1.AllowNew = false;
// 将 BindingNavigator 控件的数据来源也设定成 BindingSource 组件
//，如此一来，就可以使用 BindingNavigator 控件去导览
// DataGridView 控件中的数据列。
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;
}
// 本程序会连接至数据来源并建立所需的 DataSet 对象。
private DataSet LoadDataToDataSet()
{
// 利用 SqlConnectionStringBuilder 对象来构建连接字符串。
SqlConnectionStringBuilder sqlStringBuilder =
new SqlConnectionStringBuilder();
sqlStringBuilder.DataSource = @"(local)\SQLEXPRESS";
sqlStringBuilder.InitialCatalog = "北风贸易";
sqlStringBuilder.IntegratedSecurity = true;
// 建立一个数据集。
DataSet ds = new DataSet();
try
{
using (SqlConnection northwindConnection =
new SqlConnection(sqlStringBuilder.ConnectionString))
{
SqlCommand cmdLiming = new SqlCommand(
"SELECT 姓名,员工性别,出生日期, 目前薪资, 自传" +
" FROM dbo.飞狐工作室 WHERE 自传 IS NOT NULL",
northwindConnection);
northwindConnection.Open();
using (SqlDataReader drLiming = cmdLiming.ExecuteReader())
{
ds.Load(
drLiming,
LoadOption.OverwriteChanges,
new string[] { "飞狐工作室" });
}
}
}
catch (Exception)
{
MessageBox.Show(
"要能够顺利执行本范例程序，您的计算机必须已安装 SQL Server " +
"Express，并且必须已附加了本书所附的「北风贸易」数据库。" +
"关于如何安装 SQL Server Express，请参阅附录或相关文件说明。");
// 无法连接至 SQL Server。
return null;
}
return ds;
}
建议阅读书籍：《Visual C# 2005文件IO与数据存取秘诀》（机械工业出版社，预计2006年12月出版）。
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