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菜鸟问题求教 做一个银行的存取款系统 碰到下面问题 做到转账系统时 我思路是a用户取出钱 b用户存入钱 就在存款和取款的基础上改了一下代码 运行也不报错 就是一直没有效果 String str1 = "Server=localhost\\MSSQLSERVER1;uid=sa;pwd=sql;database=bank"; SqlConnection con = new SqlConnection(str1); con.Open(); SqlDataAdapter da3 = new SqlDataAdapter("select 账户号,金额 from card where 账户号='" + usercard3 + "'and 密码='" + userpwd31 + "'", con); DataTable dt3 = new DataTable(); da3.Fill(dt3); SqlDataAdapter da4 = new SqlDataAdapter("select 账户号,金额 from card where 账户号='" + usercard4 + "'", con); DataTable dt4 = new DataTable(); da4.Fill(dt4); textBox19.Text = dt3.Rows[0][0].ToString(); string m3 = dt3.Rows[0][1].ToString(); string m4 = dt4.Rows[0][1].ToString(); //计算总金额 float money32; money32 = Convert.ToSingle(m3); float moneyx3; moneyx3 = Convert.ToSingle(money3); float moneyxx3 = money32 - moneyx3; if (moneyxx3 < 0) { MessageBox.Show("账户金额不足!"); textBox24.Clear(); textBox14.Text = ""; textBox20.Text = ""; return; } float money42; money42 = Convert.ToSingle(m4); float moneyxx4 = money42 + moneyx3; //更新card表里金额的记录 string mon3 = moneyxx3.ToString(); string mon4 = moneyxx4.ToString(); textBox1.Text = mon3; SqlCommand com5 = new SqlCommand(); com5.CommandText = "update card set 金额='" + mon3 + "' where 账户号='" + usercard3 + "'"; com5.Connection = con; //con.Open(); com5.ExecuteNonQuery(); com5.Dispose(); con.Close(); SqlCommand com7 = new SqlCommand(); com7.CommandText = "update card set 金额='" + mon4+ "' where 账户号='" + usercard4 + "'"; com7.Connection = con; con.Open(); com7.ExecuteNonQuery(); com7.Dispose(); con.Close(); //插入记录 SqlCommand com6 = new SqlCommand(); com6.CommandText = "insert into record (账户号,日期,存取类型,存取金额)values('" + usercard3 + "','" + date1 + "','转出','" + money3 + "')"; com6.Connection = con; con.Open(); com6.ExecuteNonQuery(); com6.Dispose(); con.Close(); MessageBox.Show("操作成功!"); textBox1.Clear(); textBox21.Clear(); textBox23.Clear(); textBox20.Clear(); textBox14.Clear(); textBox19.Clear(); textBox24.Clear(); 初学 希望能有人指导下
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