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

Question

I am developing an application in C# VS 2010.

I am using CE database to this. My code to search a string from database is

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);
   }
}

When I input any string like as I am getting error System.FormatException: @name : as - Input string was not in a correct format.

What will be the error unable to fix.

Answer 1

Remove the quoting from the sql command text.
Parameters are invaluable also for helping to avoid that confusion.

Add the wildcard chars to the parameter value....

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 + "%") ;