读取 SQL 表单元格值，仅更改 ComboBox.text 而不更改 ComboBox 集合项

Posted 2023-03-23

【中文标题】读取 SQL 表单元格值，仅更改 ComboBox.text 而不更改 ComboBox 集合项

【英文标题】：Read a SQL table cell value and only change a ComboBox.text without changing the ComboBox collection items

【发布时间】：2021-04-04 20:42:12

【问题描述】：

我正在尝试为微型策略游戏制作军队列表生成器。

我想知道读取 SQL 表格单元格值并将每个单元的值放入 ComboBox.text 字段的正确方法，但仅限于字段中。

不应修改 ComBoBox 集合项（我需要它们保持原样）。我只想用红框值修改 ComboBox.text 值，并为每个单位修改

为了记录，目前，我读取了其他表信息并以这种方式将它们加载到其他组合框中：

Private Sub TextBoxQuantitéUnités_Click(sender As Object, e As EventArgs) Handles TextBoxQuantitéUnités.Click
        Dim connection As New SqlConnection("Data Source=Server;Initial Catalog=OST;Integrated Security=True")
        Dim dt As New DataTable
        Dim sqlquery As String

        connection.Open()

        sqlquery = "select * from liste1 Order By index_unité"

        Dim SQL As New SqlDataAdapter(sqlquery, connection)
        SQL.Fill(dt)

        Dim cmd As New SqlCommand(sqlquery, connection)
        Dim reader As SqlDataReader = cmd.ExecuteReader

        ComboBoxNomUnités.DataSource = dt
        ComboBoxNomUnités.DisplayMember = "nom_unité"

        ComboBoxTypeUnités.DataSource = dt
        ComboBoxTypeUnités.DisplayMember = "type_unité"

        ComboBoxAbréviationUnités.DataSource = dt
        ComboBoxAbréviationUnités.DisplayMember = "abréviation_unité"

        ComboBoxCoutTotal.DataSource = dt
        ComboBoxCoutTotal.DisplayMember = "cout_unité"

        connection.Close()
    End Sub

非常感谢:-)

The ComboBox.text where I want to load the cell value

The table picture with the framed value I want to load into the cell

The original ComboBox collection I want to keep

编辑 2：

My table structure

Your function call

A short clip of the program in order to understand my problem

如您所见，该功能看起来不错，当我在执行期间检查 ComboBoxQuality 文本时，它看起来不错，但由于某种原因，它并没有改变...

其他的组合框是同步的，你可以在上面的代码中看到。

提前谢谢...

编辑 3：

请求的整个代码：

Imports System.Data
Imports System.Data.SqlClient
Imports System.Data.Sql



Public Class FormOst
    Public Function GetStringFromQuery(ByVal SQLQuery As String) As String
        Dim CN = New SqlConnection("Data Source=Server;Initial Catalog=OST;Integrated Security=True")

        CN.Open()

        Dim StrSql As String = SQLQuery

        Dim cmdReader As SqlCommand = New SqlCommand(StrSql, CN)
        cmdReader.CommandType = CommandType.Text

        Dim SdrReader As SqlDataReader = cmdReader.ExecuteReader(CommandBehavior.CloseConnection)

        GetStringFromQuery = ""
        Try
            With SdrReader
                If .HasRows Then
                    While .Read
                        If .GetValue(0) Is DBNull.Value Then
                            GetStringFromQuery = ""
                        Else
                            If IsDBNull(.GetValue(0).ToString) Then
                                GetStringFromQuery = ""
                            Else
                                GetStringFromQuery = .GetValue(0).ToString
                            End If
                        End If
                    End While
                End If
            End With
            CN.Close()

        Catch ex As Exception
            MsgBox(SQLQuery, MsgBoxStyle.Exclamation, "Error")
        End Try
    End Function




    Private Sub TextBoListeArmées_Click(sender As Object, e As EventArgs) Handles TextBoxListeArmées.Click
        Dim connection As New SqlConnection("Data Source=Server;Initial Catalog=OST;Integrated Security=True")

        Dim dt As New DataTable
        Dim sqlquery As String

        connection.Open()

        sqlquery = "select [nom_unité] + ' | ' + [abréviation_unité] as Unité, index_unité, abréviation_unité, type_unité, qualité_unité, cout_unité from liste1 Order By index_unité"

        Dim SQL As New SqlDataAdapter(sqlquery, connection)
        SQL.Fill(dt)

        Dim cmd As New SqlCommand(sqlquery, connection)

        ComboBoxNomUnités.DataSource = dt
        ComboBoxNomUnités.DisplayMember = "Unité"
        ComboBoxNomUnités.AutoCompleteMode = AutoCompleteMode.Append
        ComboBoxNomUnités.AutoCompleteSource = AutoCompleteSource.ListItems

        ComboBoxTypeUnités.DataSource = dt
        ComboBoxTypeUnités.DisplayMember = "type_unité"

        ComboBoxAbréviationUnités.DataSource = dt
        ComboBoxAbréviationUnités.DisplayMember = "abréviation_unité"

        ComboBoxCoutUnité.DataSource = dt
        ComboBoxCoutUnité.DisplayMember = "cout_unité"

        LabelListeChargéeVisible.Enabled = True
        LabelListeChargée.Visible = True

        connection.Close()
    End Sub

    Private Sub TextBoxQuantitéUnités_KeyPress(sender As Object, e As KeyPressEventArgs) Handles TextBoxQuantitéUnités.KeyPress
        If Char.IsDigit(e.KeyChar) = False And Char.IsControl(e.KeyChar) = False Then
            e.Handled = True
        End If
    End Sub

    Private Sub TextBoxQuantitéUnités_TextChanged(sender As Object, e As EventArgs) Handles TextBoxQuantitéUnités.TextChanged
        Try
            TextBoxCoutTotal.Text = (Decimal.Parse(TextBoxQuantitéUnités.Text) * Decimal.Parse(ComboBoxCoutUnité.Text)).ToString()
        Catch ex As Exception
        End Try

    End Sub

    Private Sub ButtonEffacer_Click(sender As Object, e As EventArgs) Handles ButtonEffacer.Click
        TextBoxQuantitéUnités.Text = ""
        ComboBoxNomUnités.Text = ""
        ComboBoxTypeUnités.Text = ""
        ComboBoxQualitéUnités.Text = ""
        ComboBoxAbréviationUnités.Text = ""
        ComboBoxCoutUnité.Text = ""
        TextBoxCoutTotal.Text = ""

    End Sub



    Private Sub LabelListeChargéeVisible_Tick(sender As Object, e As EventArgs) Handles LabelListeChargéeVisible.Tick
        LabelListeChargée.Visible = False
        LabelListeChargéeVisible.Enabled = False
    End Sub

    Private Sub ComboBoxNomUnités_SelectionChangeCommitted(sender As Object, e As EventArgs) Handles ComboBoxNomUnités.SelectionChangeCommitted
        Try
            ''  TextBoxCoutTotal.Text = (Decimal.Parse(ComboBoxCoutUnité.SelectedItem.ToString) * Decimal.Parse(TextBoxQuantitéUnités.Text)).ToString
            ComboBoxQualitéUnités.Text = GetStringFromQuery("SELECT qualité_unité FROM liste1 ORDER BY index_unité")
        Catch ex As Exception
        End Try

    End Sub


End Class

【参考方案1】：

通过 sql 查询检索数据的功能

Public Function GetStringFromQuery(ByVal SQLQuery As String) As String
   Dim CN  As New SqlConnection("Data Source=Server;Initial Catalog=OST;Integrated Security=True")


    CN.Open()

    Dim StrSql As String = SQLQuery

    Dim cmdReader As SqlCommand = New SqlCommand(StrSql, CN)
    cmdReader.CommandType = CommandType.Text

    Dim SdrReader As SqlDataReader = cmdReader.ExecuteReader(CommandBehavior.CloseConnection)
    'SdrReader = cmdReader.ExecuteReader
    GetStringFromQuery = ""
    Try
        With SdrReader
            If .HasRows Then
                While .Read
                    If .GetValue(0) Is DBNull.Value Then
                        GetStringFromQuery = ""
                    Else
                        If IsDBNull(.GetValue(0).ToString) Then
                            GetStringFromQuery = ""
                        Else
                            GetStringFromQuery = .GetValue(0).ToString
                        End If
                    End If
                End While
            End If
        End With
        CN.Close()

    Catch ex As Exception
        MsgBox(SQLQuery, MsgBoxStyle.Exclamation, "Error")
    End Try
End Function

检索数据并放入您的组合框文本

ComboBox.Text = GetStringFromQuery("Enter Sql Query here")

【讨论】：

您好，Yat Fei Leong，感谢您的快速答复！好吧，也许我做错了什么，但它不起作用..我将函数放在公共类表单之后，并使用以下行调用该函数：ComboBoxQualitéUnités.Text = GetStringFromQuery("select qualité_unité from liste1 order by index_unité") 但是由于某种原因，它不起作用..（仅供参考，该函数自动将公共属性 ImporLinkCS 添加为字符串）

我已经编辑了代码。您需要将连接更改为您自己的，而不是使用我的。

感谢您的回复。我已经这样做了，但它不起作用..?

如果您使用 sql server，请尝试使用相同的 sql 使用 sql management studio 查询它是否返回任何值。很可能是sql语句问题

我用新东西编辑了我的第一篇文章（编辑 2）。该功能看起来不错，但由于某种原因，它不起作用。

【参考方案2】：

您的 sql 查询问题。 您的查询选择了所有内容，并且您想返回与您的项目相关的 UOM

 Private Sub ComboBoxNomUnités_SelectionChangeCommitted(sender As Object, e As EventArgs) Handles ComboBoxNomUnités.SelectionChangeCommitted
    Try
        Dim Product as string = ComboBoxNomUnités.Text
        ComboBoxQualitéUnités.Text = GetStringFromQuery("SELECT qualité_unité FROM liste1 Where Nom_Unité = '" & Product & "'")
    Catch ex As Exception
    End Try

End Sub

【讨论】：

像魅力一样工作。非常感谢你！ :-D