删除记录后DataGridView列消失

Question

我有一个Windows Forms DataGridView，我在其中显示两个表的组合。

我有一个删除行的delete函数。我的问题是，每当我执行删除功能时，其中一列就消失了。

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下面是在datagridview中调用表的代码

SqlDataAdapter da = new SqlDataAdapter(@"SELECT tblRequest.Id, usrTbl.nama, tblRequest.userId, tblRequest.leaveDays, tblRequest.leaveRequest, tblRequest.startDate, tblRequest.endDate, tblRequest.supId, tblRequest.permission FROM tblRequest CROSS JOIN usrTbl WHERE tblRequest.userId = usrTbl.Id AND tblRequest.supId='" + this.lblName.Text + "'", sc);

DataTable dt = new DataTable();
da.Fill(dt);

dataGridView1.DataSource = dt;

在删除操作之后消失的列是nama列，它是唯一与tblRequest联接的usrTbl实体。

我的T-SQL是

CREATE TABLE [dbo].[tblRequest] 
(
    [Id]           INT  IDENTITY (1, 1) NOT NULL,
    [userId]       INT  NOT NULL,
    [leaveDays]    INT  NOT NULL,
    [leaveRequest] TEXT NULL,
    [startDate]    TEXT NULL,
    [endDate]      TEXT NULL,
    [supId]        INT  NULL,
    [permission]   TEXT NULL,

    PRIMARY KEY CLUSTERED ([Id] ASC),

    CONSTRAINT [FK_tblRequest_ToTable] 
        FOREIGN KEY ([userId]) REFERENCES [dbo].[usrTbl] ([Id]) 
             ON DELETE CASCADE ON UPDATE CASCADE
);

我的删除代码：

string Query = "delete from tblRequest where Id='" + this.idTxt.Text + "';";

SqlConnection sqlCon = new SqlConnection(con);
SqlCommand sqlCom = new SqlCommand(Query, sqlCon);

有谁知道我做错了什么吗？