+ "'and name='"
 and前面好像没空格吧!

把Response去掉让它黄屏

单引号是英文半角吗？？

string sql = "deletefrom book where k_id='" +Convert.ToInt32( this.TextBox1.Text)+ "'。。。
连接整数的时候不用单引号吧，去掉单引号试试
string sql = "deletefrom book where k_id=" +Convert.ToInt32( this.TextBox1.Text)+ "。。。

string sql = "deletefrom book where k_id='" +Convert.ToInt32( this.TextBox1.Text)
            + "'and name='"
            + this.TextBox2.Text.ToString() + "'";
 

deletefrom  里面没空格  
and  前面少个空格  
应该  
string sql = "delete from book where k_id='" +Convert.ToInt32( this.TextBox1.Text)
            + "'   and name='"
            + this.TextBox2.Text.ToString() + "'";

你的连接字符串怎么没有用户名和密码呢？

string sql ="delete from book where k_id=" +Convert.ToInt32(this.TextBox1.Text)
            + "and name= "+ this.TextBox2.Text.ToString();
试试。我没用VS测试。你试下。
            

delete from

既然用Linq，怎么还用SQL语句？

晕~
你数据库根本都没打开!
CON.OPEN();