linqTOsql在運行時返回“指定的轉換無效”異常

Question

我有兩個linqTOsql實體，它們具有父子關系，一對多。 我遇到了一個問題，當我檢索父記錄時，我無法遍歷子表中的相關記錄。

此代碼失敗：

    public string test()
    { 
        string output;
        StreamEntry entry = genesisRepository.StreamEntries.FirstOrDefault(x => x.seID == 6);

        output = entry.seUrl.ToString() + "<br />";
        foreach(var item in entry.FieldInstance)
        {

            output = "<ul>";
            output += "<li>" + item.fiLabel.ToString() + "</li>";
            output = "</ul>";
        }
        return output;
    }

錯誤是：

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.InvalidCastException: Specified cast is not valid.

Source Error: 


Line 230:            
Line 231:            output = entry.seUrl.ToString() + "<br />";
Line 232:            foreach(var item in entry.FieldInstance)
Line 233:            {
Line 234:                


Source File: C:\pathtoscript.cs    Line: 232 

Stack Trace: 


[InvalidCastException: Specified cast is not valid.]
   System.Data.SqlClient.SqlBuffer.get_Int32() +5002837
   System.Data.SqlClient.SqlDataReader.GetInt32(Int32 i) +38
   Read_FieldInstance(ObjectMaterializer`1 ) +1993
   System.Data.Linq.SqlClient.ObjectReader`2.MoveNext() +32
   System.Data.Linq.EntitySet`1.Load() +124
   System.Data.Linq.EntitySet`1.GetEnumerator() +13

我不明白為什么stacktrace顯示int32 。 我99％肯定我一直在使用long和bigint來獲取所有ID。 只是為了涵蓋我的所有基礎，繼承父母和孩子的模型代碼：

家長：

[Table]
public class StreamEntry
{
    [HiddenInput(DisplayValue = false)]
    [Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
    public long seID { get; set; }

    /* other fields removed for brevity  */

    // relationship (one entry to many FieldInstances) 
    // uses EntitySet<FieldInstance> and OtherKey for the FK in FieldInstance 
    // which is the "Other" table.
    private EntitySet<FieldInstance> _FieldInstance = new EntitySet<FieldInstance>();
    [System.Data.Linq.Mapping.Association(Storage = "_FieldInstance", OtherKey = "fiStreamEntryID")]
    public EntitySet<FieldInstance> FieldInstance
    {
        get { return this._FieldInstance; }
        set { this._FieldInstance.Assign(value); }
    }

}

兒童：

[Table]
public class FieldInstance
{
    [Column(IsPrimaryKey = true, IsDbGenerated = true, AutoSync = AutoSync.OnInsert)]
    public long fiID { get; set; }

   /* Other field removed for brevity */ 

    [Column]
    public long fiStreamEntryID { get; set; }  // FK

    // Relationship (many FieldInstances to one StreamEntry)
    // using EntityRef<StreamEntry> and ThisKey
    // which is "This" table's FK
    private EntityRef<StreamEntry> _StreamEntry;
    [System.Data.Linq.Mapping.Association(Storage = "_StreamEntry", ThisKey = "fiStreamEntryID")]
    public StreamEntry StreamEntry
    {
        get { return this._StreamEntry.Entity; }
        set { this._StreamEntry.Entity = value; }
    }
}

什么可能導致我的演員異常？

編輯 - 添加表定義

StreamEntry表：

seid bigint notnull

seUrl nvarchar（255）notnull

seHeadline nvarchar（255）notnull

seBody ntext可以為空

seDescription nvarchar（255）可以為空

seKeywords nvarchar（255）可以為空

seTitle nvarchar（255）可以為空

seOrder bigint notnull

seDateCreated datetime notnull

seDateModified datetime notnull

StreamID bigint notnull

AllowComents位不暢

FieldInstance表：

ftID bigint notnull

ftIsRequired bit notnull

ftLabel nvarchar（50）notnull

ftStrValue nvarchar（1000）可以為空

ftDateTimeValue datetime可以為空

ftIntValue int nullable

ftDecValue十進制（18,0）可以為空

ftOrder bigint notnull

ftStreamEntryID bigint notnull --- FK到StreamEntry表

ftFieldTypeID bigint notbull

編輯 - 添加了StreamEntry記錄

這段代碼：

   public string test()
    { 
        string output;
        StreamEntry entry = genesisRepository.StreamEntries.FirstOrDefault(x => x.seID == 6);

        output = entry.seID.ToString() + "<br />";
        output += entry.seUrl + "<br />";
        output += entry.seHeadline + "<br />";
        output += entry.seBody + "<br />";
        output += entry.seDescription + "<br />";
        output += entry.seKeywords + "<br />";
        output += entry.seTitle + "<br />";
        output += entry.seOrder.ToString() + "<br />";
        output += entry.seDateCreated.ToString() + "<br />";
        output += entry.seDateModified.ToString() + "<br />";
        output += entry.StreamID.ToString() + "<br />";
        output += entry.AllowComments.ToString() + "<br />";

        return output;
    }

返回：

6

ASD

ASD

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0

2010-11-16 4:10:45 PM

2010-11-16 4:10:45 PM

75

假

Answer 1

是否有可能在不更新DBML的情況下更新基礎數據庫中的列類型？