System.FormatException：@name：as - 輸入字符串的格式不正確

Question

我正在使用C＃VS 2010開發一個應用程序。

我正在使用CE數據庫。 我從數據庫中搜索字符串的代碼是

string con = @"Data Source=|DataDirectory|\Database\Acadamy.sdf;Persist Security Info=False";
string cmd = "SELECT  sid AS [Student ID], sname AS [Student Name], contact AS [Contact No] FROM Student WHERE sname LIKE '%'+ @name +'%'";
var dt = new DataTable();
using (var a = new SqlCeDataAdapter())
{
 try
  {
   a.SelectCommand = new SqlCeCommand();
   a.SelectCommand.Connection = new SqlCeConnection(con);
   a.SelectCommand.CommandType = CommandType.Text;
   a.SelectCommand.CommandText = cmd;
   a.SelectCommand.Parameters.AddWithValue("@name", textBox1.Text);
   a.Fill(dt);
   dataGridView1.DataSource = dt;
  }
  catch (Exception ex)
   {
    MessageBox.Show(ex.Message);
   }
}

當我輸入像任何字符串as我收到錯誤System.FormatException: @name : as - Input string was not in a correct format.

什么是錯誤無法修復。

Answer 1

從sql命令文本中刪除引用。
參數對於幫助避免混淆也是非常寶貴的。

將通配符字符添加到參數值....

string cmd = "SELECT  sid AS [Student ID], sname AS [Student Name], " + 
            "contact AS [Contact No] FROM Student WHERE sname LIKE @name";
....
a.SelectCommand.Parameters.AddWithValue("@name", "%" + textBox1.Text + "%") ;