DataGridViewComboBoxCell.DataSource 屬性

參考

定義

命名空間:: System.Windows.Forms

組件:: System.Windows.Forms.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

取得或設定資料來源，其中的資料包含可能顯示在下拉式清單中的選項。

public:
 virtual property System::Object ^ DataSource { System::Object ^ get(); void set(System::Object ^ value); };

public virtual object DataSource { get; set; }

public virtual object? DataSource { get; set; }

member this.DataSource : obj with get, set

Public Overridable Property DataSource As Object

屬性值

Object

IList 或 IListSource，包含用來提供資料給此下拉式清單的值集合。預設值是 null。

例外狀況

ArgumentException

當設定這個屬性時的指定值不是 null，也不具備型別 IList 或 IListSource。

範例

下列程式碼範例示範屬性的使用 DataGridViewComboBoxColumn.DataSource 方式，這與這個屬性類似。此範例是類別概觀主題中較大範例的 DataGridViewComboBoxColumn 一部分。

private:
    DataGridViewComboBoxColumn^ CreateComboBoxColumn()
    {
        DataGridViewComboBoxColumn^ column =
            gcnew DataGridViewComboBoxColumn();
        {
            column->DataPropertyName = ColumnName::TitleOfCourtesy.ToString();
            column->HeaderText = ColumnName::TitleOfCourtesy.ToString();
            column->DropDownWidth = 160;
            column->Width = 90;
            column->MaxDropDownItems = 3;
            column->FlatStyle = FlatStyle::Flat;
        }
        return column;
    }

private:
    void SetAlternateChoicesUsingDataSource(DataGridViewComboBoxColumn^ comboboxColumn)
    {
        {
            comboboxColumn->DataSource = RetrieveAlternativeTitles();
            comboboxColumn->ValueMember = ColumnName::TitleOfCourtesy.ToString();
            comboboxColumn->DisplayMember = comboboxColumn->ValueMember;
        }
    }

private:
    DataTable^ RetrieveAlternativeTitles()
    {
        return Populate("SELECT distinct TitleOfCourtesy FROM Employees");
    }

    String^ connectionString;

private:
    DataTable^ Populate(String^ sqlCommand)
    {
        SqlConnection^ northwindConnection = gcnew SqlConnection(connectionString);
        northwindConnection->Open();

        SqlCommand^ command = gcnew SqlCommand(sqlCommand, northwindConnection);
        SqlDataAdapter^ adapter = gcnew SqlDataAdapter();
        adapter->SelectCommand = command;

        DataTable^ table = gcnew DataTable();
        adapter->Fill(table);

        return table;
    }

    // Using an enum provides some abstraction between column index
    // and column name along with compile time checking, and gives
    // a handy place to store the column names.
    enum class ColumnName
    {
        EmployeeID,
        LastName,
        FirstName,
        Title,
        TitleOfCourtesy,
        BirthDate,
        HireDate,
        Address,
        City,
        Region,
        PostalCode,
        Country,
        HomePhone,
        Extension,
        Photo,
        Notes,
        ReportsTo,
        PhotoPath,
        OutOfOffice
    };

private DataGridViewComboBoxColumn CreateComboBoxColumn()
{
    DataGridViewComboBoxColumn column =
        new DataGridViewComboBoxColumn();
    {
        column.DataPropertyName = ColumnName.TitleOfCourtesy.ToString();
        column.HeaderText = ColumnName.TitleOfCourtesy.ToString();
        column.DropDownWidth = 160;
        column.Width = 90;
        column.MaxDropDownItems = 3;
        column.FlatStyle = FlatStyle.Flat;
    }
    return column;
}

private void SetAlternateChoicesUsingDataSource(DataGridViewComboBoxColumn comboboxColumn)
{
    {
        comboboxColumn.DataSource = RetrieveAlternativeTitles();
        comboboxColumn.ValueMember = ColumnName.TitleOfCourtesy.ToString();
        comboboxColumn.DisplayMember = comboboxColumn.ValueMember;
    }
}

private DataTable RetrieveAlternativeTitles()
{
    return Populate("SELECT distinct TitleOfCourtesy FROM Employees");
}

string connectionString =
    "Integrated Security=SSPI;Persist Security Info=False;" +
    "Initial Catalog=Northwind;Data Source=localhost";

private DataTable Populate(string sqlCommand)
{
    SqlConnection northwindConnection = new SqlConnection(connectionString);
    northwindConnection.Open();

    SqlCommand command = new SqlCommand(sqlCommand, northwindConnection);
    SqlDataAdapter adapter = new SqlDataAdapter();
    adapter.SelectCommand = command;

    DataTable table = new DataTable();
    table.Locale = System.Globalization.CultureInfo.InvariantCulture;
    adapter.Fill(table);

    return table;
}

// Using an enum provides some abstraction between column index
// and column name along with compile time checking, and gives
// a handy place to store the column names.
enum ColumnName
{
    EmployeeId,
    LastName,
    FirstName,
    Title,
    TitleOfCourtesy,
    BirthDate,
    HireDate,
    Address,
    City,
    Region,
    PostalCode,
    Country,
    HomePhone,
    Extension,
    Photo,
    Notes,
    ReportsTo,
    PhotoPath,
    OutOfOffice
};

Private Function CreateComboBoxColumn() _
    As DataGridViewComboBoxColumn
    Dim column As New DataGridViewComboBoxColumn()

    With column
        .DataPropertyName = ColumnName.TitleOfCourtesy.ToString()
        .HeaderText = ColumnName.TitleOfCourtesy.ToString()
        .DropDownWidth = 160
        .Width = 90
        .MaxDropDownItems = 3
        .FlatStyle = FlatStyle.Flat
    End With
    Return column
End Function

Private Sub SetAlternateChoicesUsingDataSource( _
    ByVal comboboxColumn As DataGridViewComboBoxColumn)
    With comboboxColumn
        .DataSource = RetrieveAlternativeTitles()
        .ValueMember = ColumnName.TitleOfCourtesy.ToString()
        .DisplayMember = .ValueMember
    End With
End Sub

Private Function RetrieveAlternativeTitles() As DataTable
    Return Populate( _
        "SELECT distinct TitleOfCourtesy FROM Employees")
End Function

Private connectionString As String = _
        "Integrated Security=SSPI;Persist Security Info=False;" _
        & "Initial Catalog=Northwind;Data Source=localhost"

Private Function Populate(ByVal sqlCommand As String) As DataTable
    Dim northwindConnection As New SqlConnection(connectionString)
    northwindConnection.Open()

    Dim command As New SqlCommand(sqlCommand, _
        northwindConnection)
    Dim adapter As New SqlDataAdapter()
    adapter.SelectCommand = command
    Dim table As New DataTable()
    table.Locale = System.Globalization.CultureInfo.InvariantCulture
    adapter.Fill(table)

    Return table
End Function

' Using an enum provides some abstraction between column index
' and column name along with compile time checking, and gives
' a handy place to store the column names.
Enum ColumnName
    EmployeeId
    LastName
    FirstName
    Title
    TitleOfCourtesy
    BirthDate
    HireDate
    Address
    City
    Region
    PostalCode
    Country
    HomePhone
    Extension
    Photo
    Notes
    ReportsTo
    PhotoPath
    OutOfOffice
End Enum

備註

這個屬性通常是透過 DataGridViewComboBoxColumn.DataSource 屬性為整個儲存格資料行所設定。

可能的話，請將設定 DataSource 為只包含可能選取範圍的來源，例如選取範圍的資料行。 DisplayMember然後不需要設定屬性。但是，如果來源更為複雜，請將設定 DisplayMember 為要從中擷取可能選取範圍的屬性或資料行名稱。

如果 DataSource 設定為字串陣列，則 ValueMember 不需要設定， DisplayMember 因為陣列中的每個字串都會用於值和顯示。

變更 DataSource 屬性會導致儲存格重新初始化其 Items 集合並重新繪製本身。

當您變更屬性的值 DataSource 時，控制項會嘗試搭配新的資料來源使用 ValueMember 和 DisplayMember 屬性值，並在找不到其值時，將每個屬性設定為 null 。除非是下列其中一個重大例外狀況，否則會忽略此程式期間發生的任何例外狀況： NullReferenceException 、、 StackOverflowException 、 OutOfMemoryException 、 ExecutionEngineException ThreadAbortException 、、 IndexOutOfRangeException 或 AccessViolationException 。

DataSource設定時，會 DataGridViewComboBoxCell 附加至 Disposed 資料來源的事件。 DataGridViewComboBoxCell從卸離 DataGridView 時，不會立即釋放資源。資源 DataGridViewComboBoxCell 會在處置附加資料來源時釋出。若要立即釋放垃圾收集的資源，請將 DataSource 屬性設定為 null 。

適用於

DataGridViewComboBoxCell.DataSource 屬性

定義

屬性值

例外狀況

範例

備註

適用於

另請參閱

意見反應

其他資源