你的代码修改如下: public void SelectTable()//查询超市货物表 { int Isexist; conn = new SqlConnection("server=(local);database=Myproject;uid=sa;"); string SQL = "select * from SuperMarket where 数据字段='"+txt_selectdata.Text+"'"; (//模糊查询在分号和引号中间加个百分号 例子:数据字段 like '%"+txt_selectdata.Text+"%')
conn.Open();//打开数据库 myCmd = new SqlCommand(SQL, conn);
//Isexist = myCmd.ExecuteNonQuery(); 这里错了, 修改如下 sqldatareader myreader=cmd.executereader(); if (myreader.read()) //如果搜索到数据 { da = new SqlDataAdapter(SQL, conn); ds = new DataSet(); da.Fill(ds, "SuperMarket"); GoodsGrid.SetDataBinding(ds, "SuperMarket"); GoodsGrid.ReadOnly = true; } else //如果没有搜索到数据 { MessageBox.Show("该行数据不存在表中!"); } myCmd.Connection.Close(); }
public void SelectTable()//查询超市货物表
{
int Isexist;
conn = new SqlConnection("server=(local);database=Myproject;uid=sa;");
string SQL = "select * from SuperMarket where
数据字段='"+txt_selectdata.Text+"'"; (//模糊查询在分号和引号中间加个百分号
例子:数据字段 like '%"+txt_selectdata.Text+"%')
conn.Open();//打开数据库 myCmd = new SqlCommand(SQL, conn);
//Isexist = myCmd.ExecuteNonQuery(); 这里错了,
修改如下
sqldatareader myreader=cmd.executereader();
if (myreader.read()) //如果搜索到数据
{
da = new SqlDataAdapter(SQL, conn);
ds = new DataSet();
da.Fill(ds, "SuperMarket");
GoodsGrid.SetDataBinding(ds, "SuperMarket");
GoodsGrid.ReadOnly = true; }
else //如果没有搜索到数据
{
MessageBox.Show("该行数据不存在表中!");
}
myCmd.Connection.Close();
}
string str=comm.ExecuteScalar().tostring();返回第一行第一列的值
之后判读str是否为空~
代码如下:
public void SelectTable()//查询超市货物表
{ conn = new SqlConnection(connectstring);
string SQL = "select * from SuperMarket where "+cmb_selecttype.Text+"='"+txt_selectdata.Text+"'";
da = new SqlDataAdapter(SQL, conn);
ds = new DataSet();
da.Fill(ds, "SuperMarket");
if (ds.Tables["SuperMarket"].Rows.Count == 0)
MessageBox.Show("此数据不存在表中!");
else GoodsGrid.SetDataBinding(ds, "SuperMarket");
GoodsGrid.ReadOnly = true;
myCmd.Connection.Close();
}