SQL Query error C#: Incorrect syntax near Price

You have used comma (,) instead of using AND. I would suggest you to don’t use concatenated query use parameterized query

Refer this.

string connectionString = ConfigurationManager.ConnectionStrings["Constr"].ConnectionString;
string strQuery = "select Product_type,Product_Name,Price from Product_Details where Product_type = @ProductType AND Product_Name = @ProductName AND Price = @Price ";

using (SqlConnection conn = new SqlConnection(connectionString))
{
    using (SqlCommand comm = new SqlCommand(strQuery, conn))
    {
        using (SqlDataAdapter adp = new SqlDataAdapter(comm))
        {
            comm.Parameters.AddWithValue("@ProductType", this.ddlProductType.SelectedItem.Value);
            comm.Parameters.AddWithValue("@ProductName", this.ddlProductName.SelectedItem.Value);
            comm.Parameters.AddWithValue("@Price", this.txtPrice.Text);
            DataSet ds = new DataSet();
            adp.Fill(ds);
            GridView2.DataSource = ds;
            GridView2.DataBind();
        }
    }
}