无法将类型为“System.Data.DataView”的对象强制转换为类型“System.Data.SqlClient.SqlDataReader”。

weixin_41597676 2018-01-06 10:01:06

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切换为时间正序

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threenewbee 2018-01-07

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SqlDataReader re -> DataView re

weixin_41597676 2018-01-06

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SqlDataReader re = (SqlDataReader)SqlDataSource1.Select(DataSourceSelectArguments.Empty); 就是这一句报错呀

weixin_41597676 2018-01-06

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这是源代码呀 protected void Button1_Click(object sender, EventArgs e) { if (RadioButtonList1.Text == "护士") { SqlDataReader re = (SqlDataReader)SqlDataSource1.Select(DataSourceSelectArguments.Empty); if (re.Read()) { Session["username"] = TextBox1.Text; Session["password"] = TextBox2.Text; Response.Redirect("shouye.aspx"); } else { Response.Write("<script language='javascript'>alert('用户名或密码错误');</script>"); } } else { Response.Redirect("shenglixinghao.aspx"); } }

Imports System.Data.SqlClient Imports System.DateTime Partial Class member Inherits System.Web.UI.UserControl Dim sys As New SySDB '新增 Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click If Me.txt_num.Text = "" Then Response.Write("<script>alert('請輸入卡號!') 0 Then Response.Write("<script>alert('恭喜！你已經成功新增一個會員!')data() Me.btn_delete.Enabled = False Me.btn_edit.Enabled = False Me.txt_num.ReadOnly = False Me.txt_num.BackColor = Drawing.Color.Yellow End Sub Private Sub cleardata() Me.txt_num.Text = "" Me.txt_name.Text = "" Me.txt_age.Text = "" Me.year.Text = "" Me.sex.SelectedValue = "女" Me.txt_address.Text = "" Me.txt_email.Text = "" Me.txt_phone.Text = "" Me.txt_passport.Text = "" End Sub ' Private Sub loadmonth() ' Dim i As Integer = 1 ' For i = 1 To 12 Step 1 ' month.Items.Add(i) 'Next ' End Sub ' Private Sub loadday() ' 'Dim i As Integer ' Dim j As Integer = 1 ' For j = 1 To 31 Step 1 ' day.Items.Add(j) ' 'j = j + 1 ' Next ' End Sub Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load If Me.Page.IsPostBack = False Then load_total() End If End Sub Sub load_total() sys.SelectCommand = "SELECT count(*) as a1 FROM [member]" sys.DataSourceMode = SqlDataSourceMode.DataReader Dim dr As SqlDataReader = sys.Select() While dr.Read Me.total.Text = "現有會員:" & dr("a1") & "位" End While End Sub '查找 Protected Sub Button2_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button2.Click sys.SelectCommand = "select * from member where CardId like @CardId" sys.SelectParameters.Add(New ControlParameter("CardId", Me.txt_num.ID)) Me.Controls.Add(sys) Dim dv As Data.DataView = sys.Select(New DataSourceSelectArguments) Dim i As Integer '讀入資料，使用for循环来绑定资料　 For i = 0 To dv.Table.Rows.Count - 1 Me.txt_num.Text = dv.Table.Rows(i)("CardId").ToString Me.txt_name.Text = dv.Table.Rows(i)("name").ToString Me.txt_age.Text = dv.Table.Rows(i)("age").ToString Me.year.Text = dv.Table.Rows(i)("birthday").ToString Me.sex.SelectedValue = dv.Table.Rows(i)("sex").ToString Me.txt_address.Text = dv.Table.Rows(i)("address").ToString Me.txt_email.Text = dv.Table.Rows(i)("mail").ToString Me.txt_passport.Text = dv.Table.Rows(i)("passport").ToString Me.txt_phone.Text = dv.Table.Rows(i)("phone").ToString Next If Me.txt_num.Text <> "" Then Me.btn_delete.Enabled = True Me.btn_edit.Enabled = True Me.txt_num.ReadOnly = True Me.txt_num.BackColor = Drawing.Color.Red End If End Sub Protected Sub btn_clear_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btn_clear.Click cleardata() Me.btn_delete.Enabled = False Me.btn_edit.Enabled = False Me.txt_num.ReadOnly = False Me.txt_num.BackColor = Drawing.Color.Yellow End Sub '編輯 Protected Sub btn_edit_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btn_edit.Click Try sys.UpdateCommand = "update member set name = @name, age=@age,birthday=@birthday,sex=@sex,address=@address,mail=@mail,phone=@phone,passport=@passport where CardId=@CardId" sys.UpdateParameters.Add("name", Me.txt_name.Text.Trim.ToString) sys.UpdateParameters.Add("age", Me.txt_age.Text.Trim) sys.UpdateParameters.Add("birthday", Me.year.Text.Trim.ToString) sys.UpdateParameters.Add("sex", Me.sex.SelectedValue.ToString) sys.UpdateParameters.Add("address", Me.txt_address.Text.Trim.ToString) sys.UpdateParameters.Add("mail", Me.txt_email.Text.Trim.ToString) sys.UpdateParameters.Add("phone", Me.txt_phone.Text.Trim.ToString) sys.UpdateParameters.Add("passport", Me.txt_passport.Text.Trim.ToString) sys.UpdateParameters.Add("CardId", Me.txt_num.Text.Trim) sys.Update() Me.btn_edit.Attributes.Add("onclick", "return confirm('請先確定會員資料是否正確？')") '彈出提示窗口 If sys.Update > 0 Then Response.Write("<script>alert('會員資料更新成功!')data() Me.btn_delete.Enabled = False Me.btn_edit.Enabled = False Me.txt_num.ReadOnly = False Me.txt_num.BackColor = Drawing.Color.Yellow End Sub '刪除操作 Protected Sub btn_delete_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btn_delete.Click Try sys.DeleteCommand = "delete from member where CardId =@CardId" sys.DeleteParameters.Add("CardId", Me.txt_num.Text.Trim) sys.Delete() Me.btn_delete.Attributes.Add("onclick", "return confirm('是否要刪除此會員?')") If sys.Delete > 0 Then Response.Write("<script>alert('已經成功刪除此會員!')data() Me.btn_delete.Enabled = False Me.btn_edit.Enabled = False Me.txt_num.ReadOnly = False Me.txt_num.BackColor = Drawing.Color.Yellow End Sub End Class

DataView 类 https://docs.microsoft.com/zh-cn/dotnet/api/system.data.dataview?view=netcore-3.1 代表DataTable的可绑定数据的自定义视图，它用于排序、筛选、搜索、编辑和导航。DataView不存储数据，而改为表示对应的DataTable的连接视图。更改DataView的数据会影响DataTable。更改DataTable的数据将影响与之关联的所有DataView。 Impo...

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