c＃访问查询数据类型不匹配

Question

我试图查询一个表，但我得到一个错误，当我执行它，它只发生在我添加“Where Sdate = @ date和Staffid = @ mobile”如果我不'牛逼给它正常工作的条件，这里是代码

private void button1_Click(object sender, EventArgs e) 
{ 
    getsum(); 
} 



public void getsum() 
{ 
    string query = @"select SUM(SQuantity) AS Total FROM Sales where Sdate=@date AND Staffid=@mobile"; 
    using (var conn = new System.Data.OleDb.OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data source=|DataDirectory|\\crepeDB.accdb;")) 
      using (var cmd = new System.Data.OleDb.OleDbCommand(query, conn)) 
      { 
      cmd.Parameters.Add("@mobile", System.Data.OleDb.OleDbType.VarChar).Value = '1'; 
      cmd.Parameters.Add("@date", System.Data.OleDb.OleDbType.VarChar).Value = dateTimePicker1.Value.Date; 

      conn.Open(); 

      using (var rdr = cmd.ExecuteReader()) 
      { 
       if (rdr.Read()) 
       { 
        textBox1.Text = rdr["Total"].ToString(); 
       } 
       rdr.Close(); 
      } 
     } 
} 

希望有人能帮助我解决这个

Answer 1

尝试用其它数据类型：

cmd.Parameters.Add("@mobile", System.Data.OleDb.OleDbType.Integer).Value = 1; 
cmd.Parameters.Add("@date", System.Data.OleDb.OleDbType.DBDate).Value = dateTimePicker1.Value.Date;