Error Ado.Net/ Sql/C# need help please

Question

Exception Details: System.Data.SqlClient.SqlException: Incorrect syntax near '='.

Line 25: da = new SqlDataAdapter(strQuery, con);

Line 26: DataSet ds = new DataSet(); 

Line 27: da.Fill(ds,"Students"); 

Line 28:  

Line 29:ViewState["Sql_Query"] = strQuery;

i didnt understand why i am getting this error and how do i solve it?

my Codes:

 

string strQuery = "Select * from tblStudent where ID = " + txtID.Text;

da = new SqlDataAdapter(strQuery, con);

DataSet ds = new DataSet();

da.Fill(ds,"Students");