从数据库中检索一些数据

Question

I want to retrieve some data from the database and I have a problem

private void BindGrid()
{
    string constr = ConfigurationManager.ConnectionStrings["homeworkConnectionString2"].ConnectionString;

    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "select Id, FileName, Date from tblFiles where CourseName LIKE '%' + TextBox3.Text + '%'"; ;
            cmd.Connection = con;
            con.Open();

            GridView1.DataBind();
            con.Close();
        }
    }
}

The textbox3 have that data

So the problem I thank is with "LIKE" ?

I changed it to:

private void BindGrid()
{
    string likeCondition = string.Empty;
    string textBoxContent = TextBox3.Text;
    var splittedContents = textBoxContent.Split(',').ToList();
    int index = 0;

    foreach (var splittedContent in splittedContents)
    {
        likeCondition += "CourseName LIKE %" + splittedContent + "%";
        index++;

        if (index != splittedContent.Length)
            likeCondition += " OR ";
    }

    string constr = ConfigurationManager.ConnectionStrings["homeworkConnectionString2"].ConnectionString;

    using (SqlConnection con = new SqlConnection(constr))
    {
        using (SqlCommand cmd = new SqlCommand())
        {
            cmd.CommandText = "select Id, FileName, Date from tblFiles where " + likeCondition; ; 
            cmd.Connection = con;
            con.Open();
            GridView1.DataBind();
            con.Close();
        }
    }
}

but it still is not working - what do I have to do?

Answer 1

cmd.CommandText = "select Id, FileName, Date from tblFiles where CourseName LIKE '%' + TextBox3.Text + '%'"

your string is using the literal textbox name.

you want something like

cmd.CommandText = "select Id, FileName, Date from tblFiles where CourseName LIKE '%" + TextBox3.Text + "%'"

however, you'd be better off with paramatized queries

Answer 2

cmd.CommandText = "select Id,Name from tblName where Name LIKE '%" + TextBox1.Text + "%'"

Answer 3

You need to split up your TextBox3 content with respect to , and build your whole like condition.

I would do it in following way :

            string likeCondition = string.Empty;
            string textBoxContent = "Programming1,Database";// use TextBox3.Text here
            var splittedContents = textBoxContent.Split(',').ToList();
            int index = 0;
            foreach (var splittedContent in splittedContents)
            {

                likeCondition += "CourseName LIKE %" + splittedContent + "%";
                index++;
                if (index != splittedContent.Length)
                    likeCondition += " OR ";

            }

Now, you should use above likeCondition in your query in following way :

cmd.CommandText = "select Id, FileName, Date from tblFiles where " + likeCondition; ;