Search query on textbox only shows blank rows on datagridview.

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PICTURE BELOW.

Data Loaded

public void LoadData()    
		{
			SqlConnection con = new SqlConnection("Data Source=GH0ST;Initial Catalog=InventoryProjectDB;Integrated Security=True");
			SqlDataAdapter sda = new SqlDataAdapter(@"SELECT * FROM [dbo].[PRODUCT]", con);
			DataTable dt = new DataTable();
			sda.Fill(dt);
			dataGridView1.Rows.Clear();
			foreach (DataRow item in dt.Rows)
			{
				int ar = dataGridView1.Rows.Add();
				dataGridView1.Rows[ar].Cells[0].Value = item["PID"].ToString();
				dataGridView1.Rows[ar].Cells[1].Value = item["PName"].ToString();
				dataGridView1.Rows[ar].Cells[2].Value = item["PPrice"].ToString();
				if ((bool)item["PStatus"])
				{
					dataGridView1.Rows[ar].Cells[3].Value = "In Stock";
				}
				else
				{
					dataGridView1.Rows[ar].Cells[3].Value = "Out of Stock";
				}
				dataGridView1.Rows[ar].Cells[4].Value = item["PQTY"].ToString();
				dataGridView1.Rows[ar].Cells[5].Value = item["PDateAdded"].ToString();
			}
		}

		private void MAIN_Load(object sender, EventArgs e)
		{
			
			DateTimePicker1.Value = DateTime.Now;
			cbx_Status.SelectedIndex = 0;
			LoadData();

		}

TextChanged code

C#

private void bx_Search_TextChanged(object sender, EventArgs e)
		{
			SqlConnection con = new SqlConnection("Data Source=GH0ST;Initial Catalog=InventoryProjectDB;Integrated Security=True");
			con.Open();
			SqlDataAdapter sda = new SqlDataAdapter(@"SELECT * FROM [dbo].[PRODUCT] WHERE PNAME LIKE '%" + bx_Search.Text + "%' ", con);
			DataTable dt = new DataTable();
			sda.Fill(dt);
			dataGridView1.DataSource = dt;
			con.Close();
}

Before query:
[IMG01]
After query:
[IMG02]

What I have tried:

I am stuck and i really need to finish this project.

Posted 11-Mar-18 4:35am

S_ledge

Updated 11-Mar-18 7:57am

v3

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RickZeeland · Answer 1 · 2018-03-11T05:15:00

Solution 1

Sometimes it helps to set the .DataSource to Null first:

dataGridView1.DataSource = null;

Also see example here: DatGridView Filtering User Control[^]

Posted 11-Mar-18 5:15am

RickZeeland

Updated 11-Mar-18 5:35am

v2

Maciej Los · Answer 2 · 2018-03-11T07:58:00

Few tips:

1.
Take a look at LoadData and on bx_Search_TextChanged routine. In both you create a connection, command, etc.
The main rule of programming is: if a piece of code is used twice (or more) - change it into subroutine!

2.
Never use concatened string as a query! This is a common reason of SQL Injection[^]. The best way is to use parameterized queries[^].

3.
Use computed column of DataTable to get result of comparison "PStatus" to true/false.

Finally, your

C#

public void LoadData(string search="*")    
{
    SqlConnection con = new SqlConnection("Data Source=GH0ST;Initial Catalog=InventoryProjectDB;Integrated Security=True");
    string sql = "SELECT * FROM [dbo].[PRODUCT]";
    if(search!=string.Empty && search!="*") sql = string.Format("{0} WHERE PName Like '%{1}%'", sql, search);
    SqlDataAdapter sda = new SqlDataAdapter(sql, con);
    DataTable dt = new DataTable();
    sda.Fill(dt);
    //add expression column!
    DataColumn expressionColumn = new DataColumn("Stock", typeof(string), "IIf(PStatus=true,'In Stock','Out of Stock')");
    dt.Columns.Add(expressionColumn);
    expressionColumn.SetOrdinal(4);
    dataGridView1.DataSource = dt;
    }
}

private void bx_Search_TextChanged(object sender, EventArgs e)
{
    LoadData(bx_Search.Text)
}

For further details, please see:
Creating Expression Columns | Microsoft Docs[^]
DataColumn.Expression Property [^]