当我尝试开发无限滚动时，我遇到了一个名为 的问题connection string is not initialized，但我的其他页面使用相同的连接字符串工作正常。
我将分享我的页面，以便有人可以帮助我告诉我其中有什么问题。我认为有经验的人很容易解决我的问题。
我的 DataClass.cs在 App.data 文件夹中：
public class DataClass
{
public DataClass()
{
}
/// <summary>
/// return rows depend on position
/// if you need 10th to 20th you need to pass start=10 and end=20
/// </summary>
/// <param name="start">database start position of one row</param>
/// <param name="next">database end position of one row</param>
/// <returns></returns>
public string GetAjaxContent(int start, int end)
{
string result = string.Empty;
//adding sp params with values in Dictionary entry.
Dictionary<string, object> keyValPair = new Dictionary<string, object>();
keyValPair.Add("@start", start);
keyValPair.Add("@next", end);
DBHelper DBHelper = new DBHelper();
//passing the Stored Procedure name and keyvalue pair
DataTable dataTable = DBHelper.GetTable("spuserdata", keyValPair);
if (dataTable.Rows.Count > 0)
{
for (int i = 0; i < dataTable.Rows.Count; i++)
{
result += string.Format(@"<tr>
<td>
<table>
<tr>
<td style='width:50px;'>{0}</td><td style='width:400px;'>{1}</td><td style='width:150px;'>{2}</td>
</tr>
</table>
</td>
</tr>", dataTable.Rows[i][0].ToString(), dataTable.Rows[i][1].ToString(), dataTable.Rows[i][2].ToString());
}
}
//this string is going to append on Datalist on client.
return result;
}
/// <summary>
/// function to bind data on page load
/// </summary>
/// <returns></returns>
public DataTable FirstTenRecords()
{
Dictionary<string, object> keyValPair = new Dictionary<string, object>();
keyValPair.Add("@start", 0);
keyValPair.Add("@next", 10);
DBHelper DBHelper = new DBHelper();
DataTable dataTable = DBHelper.GetTable("spuserdata", keyValPair);
return dataTable;
}
}
public class Provider
{
public static SqlConnection GetConnection()
{
return new SqlConnection(ConfigurationManager.AppSettings["conn"]);
}
}
public class DBHelper
{
public DBHelper()
{
}
public DataTable GetTable(string SPName, Dictionary<string, object> SPParamWithValues)
{
SqlConnection conn;
SqlCommand cmd;
SqlDataAdapter adapter;
DataTable dataTable = new DataTable();
conn = Provider.GetConnection();
//open DB connection
conn.Open();
cmd = new SqlCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.Connection = conn;
cmd.CommandText = SPName;
foreach (KeyValuePair<string, object> paramValue in SPParamWithValues)
{
cmd.Parameters.AddWithValue(paramValue.Key, paramValue.Value);
}
adapter = new SqlDataAdapter(cmd);
adapter.Fill(dataTable);
return dataTable;
}
}
and my handlerr.aspx is
using System;
using System.Web;
public class Handler : IHttpHandler {
public void ProcessRequest(HttpContext context)
{
string startQstring = context.Request.QueryString["start"];
string nextQstring = context.Request.QueryString["next"];
//null check
if ((!string.IsNullOrWhiteSpace(startQstring)) && (!string.IsNullOrWhiteSpace(nextQstring)))
{
//convert string to int
int start = Convert.ToInt32(startQstring);
int next = Convert.ToInt32(nextQstring);
//setting content type
context.Response.ContentType = "text/plain";
DataClass data = new DataClass();
//writing response
context.Response.Write(data.GetAjaxContent(start, next));
}
}
public bool IsReusable {
get {
return false;
}
}
}