C# : Replace

Post by Goborijung at 2022-04-19 10:48:18 | ID: 1466

string s = "This is a book";
string rep = s.Replace("book", "pencil");

// Output : This is a pencil

C# : Set DataGridView Header

Post by Goborijung at 2020-09-14 09:04:27 | ID: 790

private void InitialGrid()
{
  //DataGridView : dgS
  dgS.Rows.Clear();
  dgS.ColumnHeadersDefaultCellStyle.BackColor = Color.Navy;
  dgS.ColumnHeadersDefaultCellStyle.ForeColor = Color.White;
  dgS.CellBorderStyle = DataGridViewCellBorderStyle.Single;
  dgS.GridColor = Color.Black;

  dgS.Columns[0].HeaderText = "Check";
  dgS.Columns[1].HeaderText = "Customer";
}

C# : Show Row Number in DataGridview | No , Row No

Post by Goborijung at 2020-10-10 14:35:55 | ID: 770

private void ShowRowNumber(DataGridView dgvName)
{
  //dgvName.RowHeadersWidth = 50;
  for (int i = 0; i < dgvName.Rows.Count; i++)
  {
    dgvName.Rows[i].HeaderCell.Value = (i + 1).ToString();
  }
  // ถ้าจะใช้ใน Function โดยตรง ให้วางไว้หลัง dgvName.DataSource = xxx;
}

C# : Show Message Dialog หรือ Message Box

Post by Goborijung at 2020-08-29 14:37:16 | ID: 759

>> Syntax 
MessageBox.Show("ข้อความ","Title");

>> ตัวอย่างที่ 1
string title    = "This is Titlle";
string message  = "Hello MessageBox";
MessageBox.Show(message); //แสดง Message Box
MessageBox.Show(message,title); //แสดง Message Box พร้อม Title

>> ตัวอย่างที่ 2
int num = 3_000_000;
MessageBox.Show(num.ToString(),"ข้อความ Title");
MessageBox.Show("Hello C#" , "This Title");

C# : Show new Form in C#

Post by Goborijung at 2020-09-02 13:06:53 | ID: 678

Syntax : FormName fn = new FormName();
fn.Show();


EX.
WEB_CuttingF4 WF4 = new WEB_CuttingF4();
WF4.Show();

C# : SQL INSERT , UPDATE , DELETE by SqlCommand

Post by Goborijung at 2020-12-04 08:23:36 | ID: 766

private void btnAddByForm_Click(object sender, EventArgs e)
{
  string name = txtName.Text.ToString();
  string sql = "INSERT INTO Employee(FirstName,LastName) VALUES('"+name+"','"+name+"')";
  //string sql = "UPDATE Employee SET FirstName='"+name+"',LastName='"+name+"' WHERE OID = "+oid+" ";
  //string sql = "DELETE Employee WHERE OID = "+oid+" ";
  SqlCommand cmd = new SqlCommand(sql, conn);
  try
  {
    conn.Open();
    cmd.ExecuteNonQuery();
    MessageBox.Show("ดำเนินการเรียบร้อยแล้ว.");
    conn.Close();

    loadDVG();
  }
  catch (Exception ex)
  {
    MessageBox.Show("Can not Open Connection! on cmdInsert");
  }
}

C# : SQL SELECT by SqlCommand

Post by Goborijung at 2020-09-10 16:00:53 | ID: 765

private void txtOID_KeyUp(object sender, KeyEventArgs e)
{
  string sql = "SELECT * FROM Employee Where OID = "+txtOID.Text.ToString()+" ";
  Console.WriteLine(sql);
  try
  {
    conn.Open();
    SqlCommand cmd = new SqlCommand(sql,conn);
    SqlDataReader dr = cmd.ExecuteReader();
    dr.Read();
    txtName.Text = dr.GetSqlValue(1).ToString(); //หรือ dr.GetValue(1).ToString(); หรือ dr["FName"].ToString();
    dr.Close();
    cmd.Dispose();
    conn.Close();
  }
  catch (Exception ex)
  {
    //MessageBox.Show("Can not Open Connection! on Keyup");
  }
  Console.WriteLine(conn.State);
}

C# : SQL SELECT by SqlDataAdapter

Post by Goborijung at 2020-09-10 16:00:25 | ID: 764

private void btnDaDs_Click(object sender, EventArgs e)
{
  string sql = "SELECT [OID],[FirstName],[LastName],[Phone],[Section] FROM Employee";
  Console.WriteLine(sql);

  SqlDataAdapter da = new SqlDataAdapter(sql, conn);
  DataSet ds = new DataSet();
  try
  {
    conn.Open();
    da.Fill(ds, "em");
    conn.Close();
    dataGridView1.DataSource = ds;
    dataGridView1.DataMember = "em";
  }
  catch (Exception ex)
  {
    MessageBox.Show("Can not Open Connection! on DataAdapter");
  }
}

C# : String to Upper()

Post by Goborijung at 2022-02-24 11:18:16 | ID: 1377

string str  = "GeeksForGeeks":
str.ToUpper();
Output: GEEKSFORGEEKS

C# : Substring Function ตัดข้อความ String

Post by Goborijung at 2020-09-22 11:26:17 | ID: 815

ตัวอย่าง

string strVal = "Hello";
strVal.Substring(0, 2);

//Output : He



// เอา 3 ตัวสุดท้าย
string str = "AM0122200204";
string substr = str.Substring(str.Length - 3); // Out : 204