System.Data.SqlClient.SqlException: 将数据类型 varchar 转换为 numeric 时出错。
public class DataBase{ public DataBase() { // // TODO: 在此处添加构造函数逻辑 // } //string strCon = "Data Source=localhost;Integrated Security=SSPI;Initial Catalog=TestOnline"; private SqlConnection SqlCon = new SqlConnection("Data Source=localhost;Integrated Security=SSPI;Initial Catalog=TestOnline"); private SqlCommand SqlCmd; // private SqlDataAdapter da; // private DataSet ds; public int GetUser(string ComStr) { SqlCon.Open(); SqlCmd = new SqlCommand(ComStr, SqlCon); int i; i = Convert.ToInt32(SqlCmd.ExecuteScalar()); return i; }} protected void Button1_Click(object sender, EventArgs e) { DataBase db = new DataBase(); if (this.TextBox1.Text.Trim() == "" || this.TextBox2.Text.Trim() == "" || this.DropDownList1.SelectedValue == "") { Response.Write("<script>alert(\"账号,密码,用户类型不能为空\");</script>"); } else { switch (DropDownList1.SelectedValue) { case "学生": string SelCmd = "SELECT COUNT(*) FROM Student WHERE Name=" + this.TextBox1.Text + "and Pwd='" + this.TextBox2.Text + "'"; // int tmp = db.GetUser(SelCmd); // Response.Write(tmp.GetType()); if (db.GetUser(SelCmd) != 0) [color=#FF0000] //System.Data.SqlClient.SqlException: 将数据类型 varchar 转换为 numeric 时出错。[/color] { Session["StuNo"] = this.TextBox1.Text; Response.Write("<script>alert(\"登陆成功\");</script>"); } else { Response.Write("<script>alert(\"账号或密码错误\");<script>"); } break; default: // Session["StuNo"] = this.TextBox1.Text; // Response.Write(Session.ToString()); break; } } }