提问人：unbeliever 提问时间：11/15/2023 更新时间：11/18/2023 访问量：36
通过 Windows 窗体应用程序查询数据后如何显示数据？
How to display data after querying it via Windows Form App?
问：
我有一个简单的 Windows 窗体应用程序，其中包含连接到我的 MariaDB 的数据网格视图。我添加了“添加条目”和“删除条目”按钮，但在添加“搜索”按钮时遇到问题。我还有六个文本框，它们代表数据库中一列的值（总共 6 列），我用它们将条目添加到网格/数据库中。我想将这些相同的文本框用于搜索功能（当我按“搜索”以显示具有该列值的所有条目时）。
这是我想出的，但最终没有奏效。我知道问题出在最后几行，我不知道如何在我的数据网格视图中显示新的数据表。提前致谢。
private void btnPretraga_Click(object sender, EventArgs e)
{
string connString = ConfigurationManager.ConnectionStrings["MariaDBConnectionString"].ConnectionString;
using (MySqlConnection konekcija = new MySqlConnection(connString))
{
konekcija.Open();
string upit = "SELECT * FROM drvnisortiment WHERE (vrstaDrveta = @VrstaDrveta OR duzinaM = @DuzinaM OR precnikCM = @PrecnikCM OR klasa=@Klasa OR redniBrDoznake=@RedniBrDoznake OR vrstaSlUzitka=@VrstaSlUzitka)";
using (MySqlCommand cmd = new MySqlCommand(upit, konekcija))
{
MySqlDataAdapter SDA = new MySqlDataAdapter(upit, connString);
cmd.Parameters.AddWithValue("@VrstaDrveta", vrstaDrvetatextBox.Text);
cmd.Parameters.AddWithValue("@DuzinaM", duzinaMtextBox.Text);
cmd.Parameters.AddWithValue("@PrecnikCM", precnikCMtextBox.Text);
cmd.Parameters.AddWithValue("@Klasa", klasatextBox.Text);
cmd.Parameters.AddWithValue("@RedniBrDoznake", redniBrDoznaketextBox.Text);
cmd.Parameters.AddWithValue("@VrstaSlUzitka", vrstaSlUzitkatextBox.Text);
DataSet ds = new DataSet();
SDA.Fill(ds, "drvnisortiment");
drvniSortimentGridView.DataSource = ds.Tables[0];
}
}
}
答：
0赞
Vector
11/18/2023
#1
此代码在包含 DataGridView 的窗体 LOADS 时运行 请考虑使用 SQLite.SQLiteDataReader
Private Sub ViewSearches()
Dim intID As Integer
Dim strDate As String
Dim strAmt As Decimal
Dim strYear As Integer
Dim strSM As Integer
Dim rowCount As Integer
Dim maxRowCount As Integer
Dim emptyStr As String = " "
Using conn As New SQLiteConnection($"Data Source = '{gv_dbName}';Version=3;")
conn.Open()
Using cmd As New SQLiteCommand("", conn)
If gvSearchType = "All" Then
cmd.CommandText = "SELECT * FROM TxData"
'cmd.Parameters.AddWithValue("$intID", intID)
'cmd.Parameters.AddWithValue("$strDate", strDate)
'cmd.Parameters.AddWithValue("$strAmt", strAmt)
'cmd.Parameters.AddWithValue("$gvYear", strYear)
'cmd.Parameters.AddWithValue("$gvSM", strSM)
ElseIf gvSearchType = "MoRangeYr" Then
'cmd.CommandText = "SELECT * FROM TxData"
'cmd.CommandText = "SELECT * FROM TxData WHERE txAmount >= '1.00' OR txAmount <= '2.00'"
cmd.CommandText = "SELECT * FROM TxData WHERE txSearchMonth >= $gvFromMonth AND txSearchMonth <= $gvToMonth AND txYear = $gvYear "
'cmd.CommandText = "SELECT * FROM TxData WHERE txSearchMonth BETWEEN $gvFromMonth AND $gvToMonth AND txYear = $gvYear "
cmd.Parameters.AddWithValue("$gvFromMonth", gvFromMonth)
cmd.Parameters.AddWithValue("$gvToMonth", gvToMonth)
cmd.Parameters.AddWithValue("$gvYear", gvYear)
End If
Using rdr As SQLite.SQLiteDataReader = cmd.ExecuteReader
'dgvTX.DataSource = rdr
'Statement Above is when DB is bound to dgvTX
'============================================
While rdr.Read()
intID = CInt((rdr("TID")))
strDate = rdr("txSortDate").ToString
strAmt = CDec(rdr("txAmount"))
strYear = CInt(rdr("txYear").ToString)
strSM = CInt(rdr("txSearchMonth").ToString) 'was txSearchMonth
'dgvTX.Columns(4).DefaultCellStyle.Format = "N"
dgvTX.Columns(2).DefaultCellStyle.Format = "C" 'Adds the $ sign and commas
dgvTX.Rows.Add(intID, strDate, strAmt, strYear, strSM, emptyStr)
rowCount = rowCount + 1
End While
If rowCount <= 25 Then
maxRowCount = 25 - rowCount
For iA = 1 To maxRowCount
dgvTX.Rows.Add(" ")
Next
End If
'dgvTX.Columns(3).DefaultCellStyle.Format = "N"
dgvTX.Sort(dgvTX.Columns(0), ListSortDirection.Ascending)
End Using
End Using
End Using
End Sub
End 类
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