问题描述
在windowsform里放了一个textbox控件,它的text是会员的ID号和两个DateTimePicker控件它们的value是查询的起始和终止时间,还有一个datagridview控件,一个button控件,它的text="查询"。我要查某个会员在某段时间里,借了些什么书。PrivateSubButton1_Click(ByValsenderAsSystem.Object,ByValeAsSystem.EventArgs)HandlesButton1.ClickForz=0ToDataGridView1.Columns.Count-1DataGridView1.Columns.RemoveAt(0)NextForz=0Toobjdataset1.Tables.Count-1DimtbAsDataTable=objdataset1.Tables(0)objdataset1.Tables.RemoveAt(0)tb.Clear()tb.Dispose()NextDataGridView1.DataMember=NothingDataGridView1.DataSource=Nothingobjcommand1.Connection=objconnection1objconnection1.Open()objcommand1.Parameters.Clear()objcommand1.CommandText="selectsh,sm,cs,zq,hq,hyhfromzsbwherertrim(ltrim(hyh))=@idandzqbetween@zq1anddateadd(mi,1439,@zq2)orderbyzq"objcommand1.Parameters.AddWithValue("@id",TextBox1.Text)objcommand1.Parameters.AddWithValue("@zq1",DateTimePicker1.Value.Date)objcommand1.Parameters.AddWithValue("@zq2",DateTimePicker2.Value.Date)objdataadapter1.SelectCommand=objcommand1objdataadapter1.Fill(objdataset1,"zsb")DataGridView1.DataSource=objdataset1DataGridView1.DataMember="zsb"DataGridView1.AutoGenerateColumns=Trueendsub第一次点击查询按扭时,datagridview能正常显示在时间段内,会员所借的书,接着改变datagridview的value也就是改变查询时间,再按查询,结果datagridview没显示一条记录,不能正常显示新时间段内,会员所借的书。请各位高人指点一下,怎么会产生这个错误。
解决方案
解决方案二:
试试:PrivateSubButton1_Click(ByValsenderAsSystem.Object,ByValeAsSystem.EventArgs)HandlesButton1.Click'Forz=0ToDataGridView1.Columns.Count-1'DataGridView1.Columns.RemoveAt(0)'NextDataGridView1.Columns.Close()DataGridView1.DataSource=nothingobjdataset1.Dispose()objcommand1.Connection=objconnection1objconnection1.Open()objcommand1.Parameters.Clear()objcommand1.CommandText="selectsh,sm,cs,zq,hq,hyhfromzsbwherertrim(ltrim(hyh))=@idandzqbetween@zq1anddateadd(mi,1439,@zq2)orderbyzq"objcommand1.Parameters.AddWithValue("@id",TextBox1.Text)objcommand1.Parameters.AddWithValue("@zq1",DateTimePicker1.Value.Date)objcommand1.Parameters.AddWithValue("@zq2",DateTimePicker2.Value.Date)objdataadapter1.SelectCommand=objcommand1objdataadapter1.Fill(objdataset1,"zsb")DataGridView1.AutoGenerateColumns=True‘最好前前面DataGridView1.DataSource=objdataset1DataGridView1.DataMember="zsb"endsub