问题描述
我需要根据一个或多个列查看具有过滤能力的大（> 10 MB，~100000行）制表符分隔文本文件。 （我不需要任何索引或编辑功能）
Hi,
I need to view large ( > 10 MB, ~100000 lines) tab delimitered text files with filtering ability according to one or more of the columns. (I do not need any sording or editing abilities)
我想到的解决方案是将delimetered文件加载到数据表中并在DataGridView控件中显示它。
The solution I thought about is loading the delimetered file into a data table and showing it in a DataGridView control.
为了获得更好的性能，我使用了http://msdn2.microsoft.com/en-us/library/ms171624.aspx 使用表格I作为数据源从文件而不是数据库连接创建。
For achieving better performance I used an caching mechanism described in http://msdn2.microsoft.com/en-us/library/ms171624.aspx using as datasource the table I created from the file instead of database connection.
尝试过滤数据时我正在使用 table.Select（filter）并使用DataRetriever返回的行class（根据上述文章）更新缓存机制。
When trying to filter the data I'm using table.Select(filter) and using the returned rows with DataRetriever class (according to the abovementioned article) to update the caching mechanism.
之后我通过 这个清除DataGridView .dgridView.Rows.Clear（）; 并通过 此 .dgridView.RowCount = retriever.RowCount来支持RowCount的属性;
Afterwards I'm clearing the DataGridView by this.dgridView.Rows.Clear(); and asigning the RowCount proprerty by this.dgridView.RowCount = retriever.RowCount;
第一个赋值（所有行）需要一段合理的时间，但是当使用过滤器放大当前显示最后一个赋值的行数时（RowCount） ）需要很长一段时间。
The first assignment (all of the rows) takes an a reasonable period of time but when using a filter that enlarges the amount of rows that currently displayed the last assignment (RowCount) takes enormous period of time.
除此之外我注意到 CellValueNeeded 和 CellFormatting 事件的火灾频率与数量不成比例当前显示的单元格，如果出现性能原因可能是一个。
Except this I noticed that the CellValueNeeded and CellFormatting events fire frequency is unproportional to the number of cells currently displayed and that may be one if the reasons for performance proplem.
我的问题是：
1。它是我能用于满足我需求的最佳控件吗？
1. Is it the best control I can use for my needs ?
2。这是我正确使用DataGridView控件的正确方法吗？
2. Is this a right way I'm using the DataGridView contol for my needs ?
2。有什么方法可以改善性能，目前的性能是不可接受的吗？
2. Is there any way I can improve the performance, current performance is unacceptable ?
谢谢，
推荐答案
private void LoadSqlData(ref DataGridView dgv,string sfilter)
{
try
{
dgv.CellValueNeeded -= new DataGridViewCellValueEventHandler(dgv_CellValueNeeded);
dgv.RowCount = 0;
dgv.Columns.Clear();
DataRetriever retriever =
new DataRetriever(project.Properties.Settings.Default.ConnectionString, "Artikelen", sfilter ); //for example "bWebEnabled=0"
memoryCache = new Cache(retriever, 50);
foreach (DataColumn column in retriever.Columns)
{
dgv.Columns.Add(
column.ColumnName, column.ColumnName);
}
dgv.RowCount = retriever.RowCount;
}
catch (SqlException se)
{
//
}
}
$
    public DataTable SupplyPageOfData（int lowerPageBoundary，int rowsPerPage）
{
//存储ID列的名称。此列必须包含唯一的
//值，以便下面的SQL能正常工作。
if（columnToSortBy == null）
{
columnToSortBy = this.Columns [0] .ColumnName;
}
if（！this.Columns [columnToSortBy] .Unique）
{
抛出新的InvalidOperationException（String.Format（&
"列{0}必须包含唯一值。"，columnToSortBy））;
  }
//从数据库中检索指定的行数，开始为
//使用lowerPageBoundary参数指定的行。
command.CommandText =" Select Top" + rowsPerPage +" " +
CommaSeparatedListOfColumnNames +"来自" + tableName +
"在哪里" + columnToSortBy +" NOT IN（选择顶部 lowerPageBoundary +" " + columnToSortBy +" From" +
tableName +" Order By" + columnToSortBy +
" ）" +（this.sfilter！= string.Empty？" AND" + sfilter +"" ;: string.Empty） +"排序依据" + columnToSortBy;
adapter.SelectCommand = command;
DataTable table = new DataTable（）;
table.Locale = System.Globalization.CultureInfo.InvariantCulture;
adapter.Fill（table）;
退货表;
} b
直到这里工作一切正常你可以看到我将sfilter添加到sql语句。
但是在过滤语句发生后我在Cache类中遇到错误。
}
public DataTable SupplyPageOfData(int lowerPageBoundary, int rowsPerPage)
{
// Store the name of the ID column. This column must contain unique
// values so the SQL below will work properly.
if (columnToSortBy == null)
{
columnToSortBy = this.Columns[0].ColumnName;
}
if (!this.Columns[columnToSortBy].Unique)
{
throw new InvalidOperationException(String.Format(
"Column {0} must contain unique values.", columnToSortBy));
}
// Retrieve the specified number of rows from the database, starting
// with the row specified by the lowerPageBoundary parameter.
command.CommandText = "Select Top " + rowsPerPage + " " +
CommaSeparatedListOfColumnNames + " From " + tableName +
" WHERE " + columnToSortBy + " NOT IN (SELECT TOP " +
lowerPageBoundary + " " + columnToSortBy + " From " +
tableName + " Order By " + columnToSortBy +
") " + (this.sfilter != string.Empty? " AND "+sfilter +" ": string.Empty) + "Order By " + columnToSortBy;
adapter.SelectCommand = command;
DataTable table = new DataTable();
table.Locale = System.Globalization.CultureInfo.InvariantCulture;
adapter.Fill(table);
return table;
}
until here works everything ok like you can see i added sfilter to sql statement.
but after filter statement happend i got error here in Cache class.
private bool IfPageCached_ThenSetElement(int rowIndex,
int columnIndex, ref string element)
{
if (IsRowCachedInPage(0, rowIndex))
{
element = cachePages[0].table
.Rows[rowIndex % RowsPerPage][columnIndex].ToString(); //here comes error
return true;
}
else if (IsRowCachedInPage(1, rowIndex))
{
element = cachePages[1].table
.Rows[rowIndex % RowsPerPage][columnIndex].ToString();
return true;
}
return false;
}
System.Data.dll中出现类型为"System.IndexOutOfRangeException"的未处理异常
¥ b $ b附加信息：位置9没有排。
b
预付款由于
djramc
An unhandled exception of type 'System.IndexOutOfRangeException' occurred in System.Data.dll
Additional information: There is no row at position 9.
thanks by advance
djramc
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