问题:对GridView的排序/ ObjectDataSource的变化取决于页
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22-07-2019 - |
题
我有一个GridView绑一个ObjectDataSource使用寻呼。分页工作正常,只是排序变化,这取决于所查看的结果页面。这将导致项目重新出现其他问题后续页。我追踪的问题到我的DAL,这一次读取一个页面,然后进行排序。显然,排序是不会改变的结果集的大小变化。是否有改进算法。我想使用DataReader如果可能的话:
[System.ComponentModel.DataObjectMethod(System.ComponentModel.DataObjectMethodType.Select)]
public static WordsCollection LoadForCriteria(string sqlCriteria, int maximumRows, int startRowIndex, string sortExpression)
{
//DEFAULT SORT EXPRESSION
if (string.IsNullOrEmpty(sortExpression)) sortExpression = "OrderBy";
//CREATE THE DYNAMIC SQL TO LOAD OBJECT
StringBuilder selectQuery = new StringBuilder();
selectQuery.Append("SELECT");
if (maximumRows > 0) selectQuery.Append(" TOP " + (startRowIndex + maximumRows).ToString());
selectQuery.Append(" " + Words.GetColumnNames(string.Empty));
selectQuery.Append(" FROM sw_Words");
string whereClause = string.IsNullOrEmpty(sqlCriteria) ? string.Empty : " WHERE " + sqlCriteria;
selectQuery.Append(whereClause);
selectQuery.Append(" ORDER BY " + sortExpression);
Database database = Token.Instance.Database;
DbCommand selectCommand = database.GetSqlStringCommand(selectQuery.ToString());
//EXECUTE THE COMMAND
WordsCollection results = new WordsCollection();
int thisIndex = 0;
int rowCount = 0;
using (IDataReader dr = database.ExecuteReader(selectCommand))
{
while (dr.Read() && ((maximumRows < 1) || (rowCount < maximumRows)))
{
if (thisIndex >= startRowIndex)
{
Words varWords = new Words();
Words.LoadDataReader(varWords, dr);
results.Add(varWords);
rowCount++;
}
thisIndex++;
}
dr.Close();
}
return results;
}
解决方案
我找到了解决此问题的阅读MSDN。关键是要执行完全查询并返回唯一有趣的子集,这样的排序始终保持一致。该程序,但是,只能使用SQL 2005。
[System.ComponentModel.DataObjectMethod(System.ComponentModel.DataObjectMethodType.Select)]
public static WordsCollection LoadForCriteria(string sqlCriteria, int maximumRows, int startRowIndex, string sortExpression)
{
//DEFAULT SORT EXPRESSION
if (string.IsNullOrEmpty(sortExpression)) sortExpression = "OrderBy";
//CREATE THE DYNAMIC SQL TO LOAD OBJECT
StringBuilder selectQuery = new StringBuilder();
selectQuery.Append("SELECT ");
selectQuery.Append(Words.GetColumnNames(string.Empty));
selectQuery.Append(" FROM (");
selectQuery.Append("SELECT ");
selectQuery.Append(Words.GetColumnNames(string.Empty));
selectQuery.Append(", ROW_NUMBER() OVER (ORDER BY " + sortExpression + ") AS RowRank");
selectQuery.Append(" FROM sw_Words) AS WordsWithRowNumbers");
selectQuery.Append(" WHERE RowRank >" + startRowIndex.ToString() + " AND " + "RowRank <=" + (startRowIndex + maximumRows).ToString());
string whereClause = string.IsNullOrEmpty(sqlCriteria) ? string.Empty : " AND " + sqlCriteria;
selectQuery.Append(whereClause);
Database database = Token.Instance.Database;
DbCommand selectCommand = database.GetSqlStringCommand(selectQuery.ToString());
//EXECUTE THE COMMAND
WordsCollection results = new WordsCollection();
int rowCount = 0;
using (IDataReader dr = database.ExecuteReader(selectCommand))
{
while (dr.Read())
{
Words varWords = new Words();
Words.LoadDataReader(varWords, dr);
results.Add(varWords);
rowCount++;
}
dr.Close();
}
return results;
}
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