#region public DataTable Search(string folderId, string searchValue, Boolean deleteMark) 查询
/// <summary>
/// 查询
/// </summary>
/// <param name=”folderId”>目录</param>
/// <param name=”searchValue”>查询条件</param>
/// <param name=”deleteMark”>删除标志</param>
/// <returns>数据表</returns>
public DataTable Search(string folderId, string searchValue, Boolean deleteMark)
{
// 一、这里是将Boolean值转换为int类型。
int delete = deleteMark ? 1: 0;
// 二、这里是开始进行动态SQL语句拼接，字段名、表明都进行了常量定义，表名字段名发生变化时，很容易就知道程序哪里都调用了这些。
string sqlQuery = string.Empty;
sqlQuery = “ SELECT “ + BaseNewsTable.FieldId
+ “ ,“ + BaseNewsTable.FieldFolderId
+ “ ,“ + BaseNewsTable.FieldTitle
+ “ ,“ + BaseNewsTable.FieldFilePath
+ “ ,“ + BaseNewsTable.FieldFileSize
+ “ ,“ + BaseNewsTable.FieldReadCount
+ “ ,“ + BaseNewsTable.FieldDescription
+ “ ,“ + BaseNewsTable.FieldCategoryCode
+ “ ,“ + BaseNewsTable.FieldEnabled
+ “ ,“ + BaseNewsTable.FieldDeleteMark
+ “ ,“ + BaseNewsTable.FieldSortCode
+ “ ,“ + BaseNewsTable.FieldCreateUserId
+ “ ,“ + BaseNewsTable.FieldCreateUserRealname
+ “ ,“ + BaseNewsTable.FieldCreateDate
+ “ ,“ + BaseNewsTable.FieldModifyUserId
+ “ ,“ + BaseNewsTable.FieldModifyUserRealname
+ “ ,“ + BaseNewsTable.FieldModifyDate
+ “ FROM “ + this.CurrentTableName
+ “ WHERE “ + BaseNewsTable.FieldDeleteMark + “ = “ + delete;
// 三、我们认为 folderId 这个查询条件是安全，不是人为输入的参数，所以直接进行了SQL语句拼接
if (!String.IsNullOrEmpty(folderId))
{
sqlQuery += “ AND “ + BaseNewsTable.FieldFolderId + “ = ‘“ + folderId + “‘“;
}
// 四、这里是进行参数化的准备，因为是多个不确定的查询参数，所以用了List。
List<DbParameter> dbParameters = new List<DbParameter>();
// 五、这里看查询条件是否为空
searchValue = searchValue.Trim();
if (!String.IsNullOrEmpty(searchValue))
{
// 六、这里是进行支持多种数据库的参数化查询
sqlQuery += “ AND (“ + BaseNewsTable.FieldTitle + “ LIKE “ + DbHelper.GetParameter(BaseNewsTable.FieldTitle);
sqlQuery += “ OR “ + BaseNewsTable.FieldCreateUserRealname + “ LIKE “ + DbHelper.GetParameter(BaseNewsTable.FieldCreateUserRealname);
sqlQuery += “ OR “ + BaseNewsTable.FieldContents + “ LIKE “ + DbHelper.GetParameter(BaseNewsTable.FieldContents);
sqlQuery += “ OR “ + BaseNewsTable.FieldDescription + “ LIKE “ + DbHelper.GetParameter(BaseNewsTable.FieldDescription) + “)“;
// 七、这里是判断，用户是否已经输入了%
if (searchValue.IndexOf(“%“) < 0)
{
searchValue = “%“ + searchValue + “%“;
}
// 八、这里生成支持多数据库的参数
dbParameters.Add(DbHelper.MakeInParam(BaseNewsTable.FieldTitle, searchValue));
dbParameters.Add(DbHelper.MakeInParam(BaseNewsTable.FieldCreateUserRealname, searchValue));
dbParameters.Add(DbHelper.MakeInParam(BaseNewsTable.FieldContents, searchValue));
dbParameters.Add(DbHelper.MakeInParam(BaseNewsTable.FieldDescription, searchValue));
}
// 九、这里是将List转换为数组，进行数据库查询
return DbHelper.Fill(sqlQuery, dbParameters.ToArray());
}
#endregion
原文链接：https://www.cnblogs.com/jirigala/archive/2010/07/28/1787291.html
原创文章，作者：优速盾-小U，如若转载，请注明出处：https://www.cdnb.net/bbs/archives/17216
