what is the code that support arabic text in C#?

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C#

C#4.0

hi I'm beginner in C# programming
I'm writeing the program: a arabic to persian Dictionary!
in my form I have a text box that take Arabic text an search it in my SQL Database
my table in Database contains of 3 column:
"arabicDictionary:nvarchar"
"farsiDictionary:nvarchar"
"voice:varbinary(max)"
I wrote my search like this:

private void toolStripButton4_Click(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection("server=.;database=MyDictionary;integrated security = true");
            SqlDataAdapter DA = new SqlDataAdapter();
            DataSet DS = new DataSet();
            try
            {
                DA.SelectCommand = new SqlCommand();
                DA.SelectCommand.Connection = con;
                DA.SelectCommand.CommandText =
                    "SELECT *From Dictable where ArabicDictionary = " + searchText.Text;
                   
                con.Open();
                DA.Fill(DS, "Dictable");
                con.Close();
                dataGridView1.AutoGenerateColumns = true;
                dataGridView1.DataSource = DS;
                dataGridView1.DataMember = "Dictable";
                DA = null;
                con = null;
            
            }
            catch (Exception ex)
            {
                MessageBox.Show (ex.Message);
            }
        }

-----------------
but it dosent work!!!!
it errors"invalid column nam"!!!
I think It's beacause I should write a code that support Arabic but I dont know how Do it :-(
please help me
thanks :)