SafeToPrepareAttribute 類別

語法

'宣告
Public NotInheritable Class SafeToPrepareAttribute _
    Inherits Attribute
'用途
Dim instance As SafeToPrepareAttribute

public sealed class SafeToPrepareAttribute : Attribute

public ref class SafeToPrepareAttribute sealed : public Attribute

[<SealedAttribute>]
type SafeToPrepareAttribute =  
    class
        inherit Attribute
    end

public final class SafeToPrepareAttribute extends Attribute

備註

If a user defined function (UDF) returns a DataTable, the UDF should be able to prepare for execution by running with the ExecuteForPrepare property set to true. To prepare for execution, the UDF should determine the structure of the DataTable needed to be returned, and return an empty DataTable that is structured appropriately.

範例

In the following example, a simple UDF creates a DataTable. If the UDF runs with the ExecuteForPrepare property set to true, the UDF returns with an empty version of the DataTable. If the UDF runs with the ExecuteForPrepare property set to false, the UDF continues, populates the DataTable, and returns the populated DataTable.

[SafeToPrepare(true)]
public System.Data.DataTable GetPreparedTable()
{
    System.Data.DataTable results = new System.Data.DataTable();
    results.Columns.Add("A", typeof(int));
    results.Columns.Add("B", typeof(string));

    if (Context.ExecuteForPrepare)
    {
        // If preparing, return just the schema with no data
        return results;
    }

    //Otherwise return data
    object[] row = new object[2];
    row[0] = 1;
    row[1] = "A";
    results.Rows.Add(row);

    row[0] = 2;
    row[1] = "B";
    results.Rows.Add(row);

    return results;
}

繼承階層

System. . :: . .Object
  System. . :: . .Attribute
    Microsoft.AnalysisServices.AdomdServer..::..SafeToPrepareAttribute

執行緒安全性

這個類型的任何公用static (在 Visual Basic 中為 Shared) 成員都是安全執行緒。不保證任何執行個體成員都可以是安全執行緒。

請參閱

參考