Question

我的系统有一个小问题，这是我插入数据时的问题，该数据将显示在DatagridView中，现在，如果我再次插入其他数据，则{{1}中的第一个数据}将被删除，并将被第二个数据替换。听起来很简单，但是我尝试了所有类似的操作，复制了相同的代码，搜索到互联网，但是仍然遇到相同的问题。

我也使用DatagridView来查看代码去向和触发什么。

到目前为止，这是我的代码。

Breakpoint

当我添加数据并单击按钮显示按钮时。结果还可以。

现在，如果我再次添加数据。第一个数据将删除并替换为第二个数据。

如结果2所示，有一个空白If TxtRod_ID.Text = "" Then MsgBox("Please enter RD Code.") : Exit Sub If rbRD.Checked = False And rbOSS.Checked = False Then MsgBox("Please select User On.") : Exit Sub Dim cn As New OleDbConnection Dim strUser As String = "" Dim cmd As OleDbCommand Dim dr As OleDbDataReader If rbRD.Checked = True Then RoDID = TxtRod_ID.Text RdGetSrvr() cn = New OleDbConnection(RDcon) Try If cn.State = ConnectionState.Closed Then cn.Open() Catch ex As Exception MessageBox.Show("Cannot connect to the database. Please contact the administrator.", "ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error) Exit Sub End Try If rbUserName.Checked = True Then If txtFname.Text.Trim() = "" And txtLname.Text.Trim() = "" Then MsgBox("Please enter First and/or Last Name of User.") : Exit Sub strUser = "select * from USERS..MS_User where First_Name like '%" & txtFname.Text.Trim() & "%' and Last_Name like '%" & txtLname.Text.Trim() & "%'" ElseIf rbUserId.Checked = True Then If txtUserID.Text.Trim() = "" Then MsgBox("Please enter User ID.") : Exit Sub strUser = "select * from USERS..MS_User where User_ID like '%" & txtUserID.Text.Trim() & "%'" End If Else If rbUserId.Checked = True Then If txtUserID.Text.Trim() = "" Then MsgBox("Please enter User ID.") : Exit Sub COGetSrvr() cn = New OleDbConnection(COcon) cn.Open() strUser = "select * from objUsr..user_locked_tbl where UserName like '%" & txtUserID.Text.Trim() & "%'" End If End If cmd = New OleDbCommand(strUser, cn) dr = cmd.ExecuteReader() Dim ctr As Integer = 0 If dr.HasRows Then While dr.Read dgUser.Rows.Add() If rbRD.Checked = True Then dgUser("dgUserID1", ctr).Value = dr("User_ID") dgUser("dgFname1", ctr).Value = dr("First_Name") dgUser("dgLname1", ctr).Value = dr("Last_Name") dgUser("dgPrimaryRole1", ctr).Value = dr("Primary_Role") dgUser("dgUserStatus1", ctr).Value = dr("User_Status") dgUser("dgULoginCnt1", ctr).Value = dr("Unsuccessful_Login_Count") dgUser("dgDesig1", ctr).Value = dr("Designation") Else dgUser("dgUserID1", ctr).Value = dr("UserName") dgUser("dgFname1", ctr).Value = "" dgUser("dgLname1", ctr).Value = "" dgUser("dgPrimaryRole1", ctr).Value = "" dgUser("dgUserStatus1", ctr).Value = "" dgUser("dgULoginCnt1", ctr).Value = "" dgUser("dgDesig1", ctr).Value = "" End If End While Else MsgBox("No record found.") Exit Sub End If End Sub，当我将其插入到我的代码row中时，当然会删除空白dgUser.Rows.Clear，但我得到了相同的结果问题。

我要实现的是，如果我插入第一个数据，则在插入第二个数据时不会将其删除。

Answer 1

好像标志“ ctr”在循环中没有改变。它是关于放置的结果的行号的吗？那么所有结果都放在同一个地方吗？

Answer 2

  Dim ctr As Integer = 0
    If dr.HasRows Then
        While dr.Read
            For ctr = 0 To dgUser.Rows.Count - 1
            Next
            dgUser.Rows.Add()
            If rbRD.Checked = True Then
                dgUser("dgUserID", ctr).Value = If(IsDBNull(dr("User_ID")) = True, "", dr("User_ID"))
                dgUser("dgFname", ctr).Value = If(IsDBNull(dr("First_Name")) = True, "", dr("First_Name"))
                dgUser("dgLname", ctr).Value = If(IsDBNull(dr("Last_Name")) = True, "", dr("Last_Name"))
                dgUser("dgPrimaryRole", ctr).Value = If(IsDBNull(dr("Primary_Role")) = True, "", dr("Primary_Role"))
                dgUser("dgUserStatus", ctr).Value = If(IsDBNull(dr("User_Status")) = True, "", dr("User_Status"))
                dgUser("dgULoginCnt", ctr).Value = If(IsDBNull(dr("Unsuccessful_Login_Count")) = True, "", dr("Unsuccessful_Login_Count"))
                dgUser("dgDesig", ctr).Value = If(IsDBNull(dr("Designation")) = True, "", dr("Designation"))
            Else
                dgUser("dgUserID", ctr).Value = If(IsDBNull(dr("UserName")) = True, "", dr("UserName"))
                dgUser("dgFname", ctr).Value = ""
                dgUser("dgLname", ctr).Value = ""
                dgUser("dgPrimaryRole", ctr).Value = ""
                dgUser("dgUserStatus", ctr).Value = ""
                dgUser("dgULoginCnt", ctr).Value = ""
                dgUser("dgDesig", ctr).Value = ""
            End If

            ctr += 1
        End While

我明白了。我只是忘记在代码中插入For Loop。感谢@Terry D的想法。

为什么单击显示时总是替换第一个数据？

2 个答案: