如何从web.config里获取connectionString的值

首先在web.config里定义了连接字符串：

<configuration>

...

<connectionStrings>

<add name="eoexmaConnectionString" connectionString="Data Source=127.0.0.1;Initial Catalog=eoexma;Integrated Security=True"

providerName="System.Data.SqlClient" />

</connectionStrings>

...

</configuration>



在DAO文件夹下新建SqlDAO.cs类文件：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Data;

using System.Data.SqlClient;

using System.Configuration;

namespace Web.DAO

{

public class SqlDAO

{

private SqlConnection m_conn = null;

private SqlCommand m_SqlCommand = null;

SqlTransaction m_SqlTransaction = null;

public SqlDAO()

{

string connString = ConfigurationManager.ConnectionStrings["eoexmaConnectionString"].ConnectionString;

m_conn = new SqlConnection(connString);

m_SqlCommand = new SqlCommand();

m_SqlCommand.Connection = m_conn;

m_conn.Open();

}

public void BeginTrans()

{

m_SqlTransaction = m_conn.BeginTransaction();

}

public void CommitTrans()

{

m_SqlTransaction.Commit();

m_SqlTransaction = null;

}

public void Rollback()

{

m_SqlTransaction.Rollback();

m_SqlTransaction = null;

}

public void Open()

{

if (this.m_conn.State == ConnectionState.Closed)

{

m_conn.Open();

}

}

public void Close()

{

m_conn.Close();

}

public int ExecuteNonQuery(string sql, CommandType commandType, string[] sqlParams, object[] values)

{

m_SqlCommand.CommandText = sql;

m_SqlCommand.CommandType = commandType;

m_SqlCommand.Transaction = m_SqlTransaction;

m_SqlCommand.Parameters.Clear();

for (int i = 0; i < sqlParams.Length; i++)

{

SqlParameter param = new SqlParameter(sqlParams[i], values[i]);

m_SqlCommand.Parameters.Add(param);

}

return m_SqlCommand.ExecuteNonQuery();

}

public int ExecuteNonQuery(string sql)

{

m_SqlCommand.CommandText = sql;

m_SqlCommand.CommandType = CommandType.Text;

m_SqlCommand.Transaction = m_SqlTransaction;

m_SqlCommand.Parameters.Clear();

return m_SqlCommand.ExecuteNonQuery();

}

public DataSet ExecuteQuery(string sql, CommandType commandType, string[] sqlParams, Object[] values)

{

m_SqlCommand.CommandText = sql;

m_SqlCommand.CommandType = commandType;

m_SqlCommand.Transaction = m_SqlTransaction;

m_SqlCommand.Parameters.Clear();

for (int i = 0; i < sqlParams.Length; i++)

{

SqlParameter param = new SqlParameter(sqlParams[i], values[i]);

m_SqlCommand.Parameters.Add(param);

}

SqlDataAdapter sda = new SqlDataAdapter(m_SqlCommand);

DataSet ds = new DataSet();

sda.Fill(ds);

return ds;

}

public DataSet ExecuteQuery(string sql)

{

m_SqlCommand.CommandText = sql;

m_SqlCommand.CommandType = CommandType.Text;

m_SqlCommand.Transaction = m_SqlTransaction;

m_SqlCommand.Parameters.Clear();

SqlDataAdapter sda = new SqlDataAdapter(m_SqlCommand);

DataSet ds = new DataSet();

sda.Fill(ds);

return ds;

}

}

}



在Default.aspx.cs里使用：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

namespace Web

{

public partial class _Default : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

if (!IsPostBack)

{

this.GridView1.DataSource = new DAO.MYDAO().getAllInfo();

this.GridView1.DataBind();

}

}

}

}



即可。